A2 — Lesson 23

Stories, Experiences & Facts

Past Simple · Present Perfect · Zero Conditional
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Vocabulary: Time, Experiences & Facts

Context: To use the Past Simple and Present Perfect correctly, you need the right time words. The two tenses often use the same verbs — but the time expressions tell you which tense to use.

1. Time Expressions — Past Simple (specific, finished time)

Yesterday/ˈjes.tə.deɪ/Вчера
Last week / month / year/lɑːst/Миналата седмица / месец / година
... ago/əˈɡəʊ/Преди ... (two days ago = преди два дни)
In 2010/ɪn/В 2010 г. — specific year in the past
This morning / evening/ðɪs/Тази сутрин / вечер (if that time is finished)

2. Time Expressions — Present Perfect (experience / recent / ongoing)

Already/ɔːlˈred.i/Вече (affirmative — done sooner than expected)
Yet/jet/Още / Вече (negatives and questions)
Just/dʒʌst/Току-що (completed very recently)
Ever/ˈev.ər/Някога (in questions about life experience)
Never/ˈnev.ər/Никога (negative life experience)
Since/sɪns/От + точен момент (since 2015 / since Monday)
For/fɔː/От / За + период (for three years / for a week)
Recently/ˈriː.sənt.li/Наскоро

3. Life Events & Experiences

To graduate/ˈɡræd.ʒu.eɪt/Завършвам (университет)
To move (house)/muːv/Мествам се
To discover/dɪˈskʌv.ər/Откривам
To achieve/əˈtʃiːv/Постигам
To experience/ɪkˈspɪər.i.əns/Преживявам / Изпитвам
To try/traɪ/Опитвам (нова храна, ново нещо)

4. Zero Conditional Context

Condition/kənˈdɪʃ.ən/Условие (the "if" part)
Result/rɪˈzʌlt/Резултат (what always happens)
Fact/fækt/Факт
📝 Exercise A — PS or PP? Does this time expression signal Past Simple or Present Perfect? Choose PS or PP.
1. "yesterday"
2. "already"
3. "in 2015" (a specific year)
4. "never"
5. "last week"
6. "since Monday"
🎯 Exercise B — FOR or SINCE? Type FOR or SINCE.
1. She has worked here ___ 2018.
2. They have been married ___ twenty years.
3. I haven't seen him ___ last Christmas.
4. He has played the guitar ___ five years.
5. She has lived in Sofia ___ she graduated.

Grammar Lab

Five sections. Read every explanation before the exercises.
1

Zero Conditional — Core Rules

Always true — scientific facts, natural laws, personal habits

We use the Zero Conditional for things that are always true — scientific facts, natural laws, and personal habits. The result is 100% certain every single time. It is not a prediction and it is not about the future. Both parts of the sentence use the Present Simple.

Structure & Examples

  • If / When + Present Simple, + Present Simple
  • "If you heat water to 100°C, it boils."
  • "If I don't sleep, I feel tired."
  • "When it rains, the streets get wet."
  • ⚠️ Never use WILL in the Zero Conditional.

What it is NOT

  • ❌ "If you heat water, it will boil." — this is First Conditional (possible future), not Zero.
  • ✅ "If you heat water, it boils." — Zero, always true.
  • You can use when instead of if for things that always happen without exception.

Common Topics

  • Science / nature: "If you freeze water, it turns to ice."
  • Personal habits: "If I drink coffee at night, I don't sleep well."
  • Rules / instructions: "If you press this button, the machine starts."
  • General truths: "If children are tired, they get upset easily."
📝 Exercise A — Easy: Complete the zero conditional. Write the correct present simple form.
1. If you heat water to 100°C, it ___ (boil).
2. If I don't sleep, I ___ (feel) tired.
3. If it rains, the street ___ (get) wet.
4. If you mix red and blue, you ___ (get) purple.
5. If animals don't eat, they ___ (die).
🎯 Exercise B — Harder: Write the full zero conditional result clause starting from the word given.
1. "If you don't water plants, ___" → they ___ (die).
2. "If I eat too much sugar, ___" → I ___ (feel) sick.
3. "When she doesn't go to the gym, ___" → she ___ (feel) tired.
4. "If you mix yellow and blue, ___" → you ___ (get) green.
2

If vs When · Imperative Results

Two extra patterns that still belong to the Zero Conditional

Two things often confuse students at this level: when to use "when" instead of "if", and the fact that the result clause can be an imperative (an instruction) instead of Present Simple.

If vs When

  • If = it may or may not happen (a real possibility, not certain)
  • "If it rains, I take an umbrella." (it might not rain)
  • When = it definitely happens, regularly or inevitably
  • "When the sun sets, it gets dark." (always happens)
  • Both are grammatically Zero Conditional — Present Simple + Present Simple

Imperative Result

  • The result clause can be an order / instruction / advice, not a fact
  • "If you feel cold, close the window."
  • "If the alarm rings, leave the building immediately."
  • "When you finish the test, put down your pen."
  • This is still Zero Conditional — the "if" part is Present Simple
💡 Quick test: Could the situation reasonably not happen? → use if. Does it always / inevitably happen? → when usually sounds more natural. Both are still correct grammar in most everyday sentences.
📝 Exercise A — Easy: Choose IF or WHEN — whichever fits best.
1. ___ the sun goes down, it gets dark. (always true)
2. ___ I have time tomorrow, I'll call you. (not certain)
3. ___ water freezes, it becomes ice. (always true)
4. ___ you win the lottery, what will you do? (very unlikely)
🎯 Exercise B — Harder: Complete the imperative result clause with the verb in brackets.
1. If you feel tired, ___ (go) to bed early.
2. If the phone rings, ___ (not / answer) it — it's probably spam.
3. When you arrive, ___ (call) me immediately.
4. If you don't understand a word, ___ (look) it up in a dictionary.
3

Negative Conditions

Making the "if" clause, the result, or both negative

Either half of a Zero Conditional sentence can be negative — the condition, the result, or both. The rule doesn't change: Present Simple in both clauses, just with "don't / doesn't" added where needed.

Negative Condition

  • don't / doesn't + base verb in the if-clause
  • "If you don't water plants, they die."
  • "If she doesn't sleep, she feels tired."

Negative Result

  • don't / doesn't + base verb in the result clause
  • "If you heat ice, it doesn't stay solid."
  • "If it doesn't rain, the grass doesn't grow."

Both Negative

  • Negative + negative is completely normal
  • "If you don't practise, you don't improve."
  • "If plants don't get sunlight, they don't grow."
⚠️ Common mistake: students often forget "do/does" and write "If you not water plants..." — always keep don't / doesn't + base verb, never just "not".
📝 Exercise A — Easy: Make the verb in brackets negative.
1. If you ___ (not / eat) breakfast, you feel hungry by 11am.
2. If she ___ (not / study), she fails the test.
3. If plants don't get water, they ___ (not / grow).
4. If you ___ (not / charge) your phone, it ___ (not / work).
🎯 Exercise B — Harder: Rewrite the sentence so the underlined idea becomes negative, keeping the zero conditional.
1. "If you water plants, they grow." → Make it negative: If you ___, they ___.
2. "If I sleep eight hours, I feel great." → Negative result: If I sleep eight hours, I ___.
3. "If it rains, the grass grows." → Negative condition: If it ___, the grass doesn't grow.
4. "If you practise, you improve." → Both negative: If you ___, you ___.
4

Questions & Short Answers

Asking about facts, habits, and rules with the Zero Conditional

To make a Zero Conditional question, invert the result clause (Do/Does + subject + base verb?) — the if-clause never changes. Short answers use Do/Does, not Is/Are or Will, because the whole sentence is Present Simple.

Structure

  • If-clause stays the same: If + subject + present simple
  • Question part: Do/Does + subject + base verb?
  • "If you heat ice, does it melt?"
  • "Do plants die if they don't get water?"
  • The question word order can go before or after the if-clause

Short Answers

  • Yes, it does. / No, it doesn't.
  • Yes, they do. / No, they don't.
  • ⚠️ NOT "Yes, it is" or "Yes, it will" — Zero Conditional is Present Simple, so short answers use do/does
  • "Does metal expand if you heat it?" — "Yes, it does."
💡 Word order tip: You can ask "Does it melt if you heat ice?" or "If you heat ice, does it melt?" — both are correct. The question form only applies to the clause that is NOT the if-clause.
📝 Exercise A — Easy: Choose the correct short answer.
1. "Does water freeze if the temperature drops?"
2. "Do plants grow if they don't get sunlight?"
3. "Does she feel tired if she doesn't sleep?"
4. "Do metals conduct electricity if they get wet?"
🎯 Exercise B — Harder: Write the missing question word(s) (Do / Does).
1. ___ ice melt if you heat it?
2. If you don't water plants, ___ they die?
3. ___ he get angry if you arrive late?
4. If the alarm rings, ___ everyone leave the building?
5

Other Conjunctions

Unless · As soon as · Until — alternatives to if / when

"If" and "when" aren't the only conjunctions that work with the Zero Conditional. Unless, as soon as, and until follow the same rule — Present Simple in both clauses — but each adds a slightly different meaning.

Unless

  • = if ... not (a negative condition built into one word)
  • "Plants die unless they get water." (= if they don't get water)
  • "I don't feel well unless I sleep eight hours."
  • ⚠️ Never add "not" after unless — it's already negative

As Soon As

  • = immediately when
  • "The alarm rings as soon as someone opens the door."
  • "Metal rusts as soon as it gets wet, if it isn't protected."

Until

  • = up to the moment when (continues, then stops/changes)
  • "Water doesn't boil until it reaches 100°C."
  • "A baby can't walk until its muscles are strong enough."
⚠️ Unless = if + not: "Unless you study, you fail" means the same as "If you don't study, you fail." Saying "unless you don't study" is a common mistake — it's a double negative.
📝 Exercise A — Easy: Choose UNLESS, AS SOON AS, or UNTIL.
1. Water doesn't freeze ___ the temperature drops below 0°C.
2. I switch off the light ___ I leave a room.
3. Plants don't survive ___ they get enough light.
4. The shop doesn't open ___ it's 9 o'clock.
5. He gets a headache ___ he eats breakfast.
🎯 Exercise B — Harder: Rewrite each sentence using UNLESS instead of "if ... not."
1. "If you don't water plants, they die." → ___
2. "If she doesn't study, she fails." → ___
3. "If you don't book early, tickets sell out." → ___
🎯 Exercise C — Mixed: Complete with the correct present simple form of the verb in brackets.
1. The milk goes bad unless you ___ (keep) it in the fridge.
2. As soon as the bell ___ (ring), the students stand up.
3. A fruit isn't ripe until it ___ (change) colour.
4. Unless you ___ (practise) every day, you don't improve.

Reading: Zero Conditional in Context

Read each text carefully, then choose the best answer. Press Check Answers when you finish each text. All four texts focus on the Zero Conditional — matching the 5 parts of Grammar Lab.
🔬

Text 1: The Science Classroom

Mrs Kovacheva is a science teacher at a secondary school in Plovdiv. Every year, she introduces her students to zero conditional sentences, which she uses to explain scientific facts and general truths. "If you heat water to one hundred degrees Celsius, it boils," she explains. "If you mix yellow and blue paint, you get green. If you leave bread in a warm, damp place for several days, mould grows on it." She also gives examples from daily life: "If you eat too much sugar, your teeth get damaged. If you do not sleep enough, your body does not function properly." Mrs Kovacheva always reminds her students of one important rule: "We use the present simple in BOTH parts of the sentence. There is no future tense. The result is always true — it is not a prediction or a possibility. It is simply a fact."

Questions:

1. What does Mrs Kovacheva use zero conditional sentences to explain?

2. What happens if you mix yellow and blue paint?

3. What tense is used in BOTH parts of a zero conditional?

4. According to Mrs Kovacheva, the zero conditional describes:

🏃

Text 2: Maya's Health Rules

Maya is a graphic designer who lives in Sofia. She has a simple set of health rules, and she follows them every day. "If I exercise regularly, I feel much better and I sleep well," she says. "But if I don't go to the gym for more than a week, I feel tired and I don't concentrate well at work." When she feels stressed, she goes for a run — as soon as she finishes, her mood always improves. Unless she sleeps at least seven hours, she gets a headache the next morning, so she always tries to go to bed early. "If you feel cold in the evening," she tells her flatmates, "close the window before you go to sleep — the heating doesn't work well until the room warms up properly." Maya believes these small habits make a big difference. "Do you feel better if you exercise?" her friends often ask her. "Yes, I do," she always replies. "And if I don't move my body, I don't feel like myself."

Questions:

1. What happens if Maya doesn't go to the gym for more than a week?

2. "Unless she sleeps at least seven hours, she gets a headache." This means the same as:

3. What does Maya tell her flatmates to do if they feel cold?

4. "Do you feel better if you exercise?" — "Yes, ___." What completes Maya's short answer correctly?

🌱

Text 3: Plamen's Balcony Garden

Plamen grows tomatoes and herbs on his balcony in Plovdiv, and he loves explaining his simple gardening rules to his neighbours. "Plants don't survive unless they get enough light," he tells them, "so I always put mine near the window." He waters them every morning, because if he doesn't water them, they die within a few days in the summer heat. "As soon as the soil feels dry, I know it's time to water again," he explains. He never uses chemical fertiliser. "Unless you use natural compost, the tomatoes don't taste as good," he insists. His neighbour Ivan once asked him, "Does it really make a difference if you talk to your plants?" Plamen laughed. "No, it doesn't," he admitted, "but it makes ME feel better!" When the first frost comes in autumn, Plamen brings the herb pots inside. "Basil doesn't survive outdoors until spring," he says, "so I keep it on the kitchen windowsill all winter." If anyone asks for advice, Plamen always says the same thing: "If you don't try, you don't learn — so just start, even with one small pot."

Questions:

1. According to Plamen, what do plants need to survive?

2. "Basil doesn't survive outdoors until spring." This means basil:

3. "Does it make a difference if you talk to your plants?" — "No, ___." What is the correct short answer?

4. What does Plamen always say to people who ask for gardening advice?

🚆

Text 4: Station Rules

At Sofia Central Station, a guard explains the rules to a group of new staff. "If the alarm rings, leave the building immediately — don't wait for instructions," he says firmly. "When a train arrives, the doors open automatically, but they don't open if the train hasn't stopped completely." He continues with more advice: "Unless a ticket is valid, passengers can't board the train. As soon as you see a problem on the platform, you call the main office — you don't wait." One of the new staff asks, "Do passengers need a ticket for the platform, or just for the train?" "They need one for both," the guard replies. Another trainee asks, "Does the system close automatically at night?" "Yes, it does," the guard answers. "Unless there's a special late service, the station closes at midnight and doesn't reopen until five in the morning." He finishes with the most important rule of all: "If you don't know an answer, don't guess — ask a senior colleague. We don't take risks with passenger safety here."

Questions:

1. What should staff do if the alarm rings?

2. "Unless a ticket is valid, passengers can't board the train." This means passengers can board only if:

3. "Does the system close automatically at night?" — "Yes, ___." What is the correct short answer?

4. What is the guard's most important rule for new staff?

Text 1 / 4

Cloze Text: Rules for Everyday Life

Choose the correct word or phrase. The text tests all 5 parts of the Zero Conditional from Grammar Lab: core rules, if vs when, imperatives, negative conditions, questions & short answers, and conjunctions.

Rules for Everyday Life

Borislav loves explaining simple rules to his students. "If you (1) water to 100°C, it (2) — that never changes," he says. He also likes to point out that (3) the sun sets, it always gets dark, but he prefers "if" for things that are not certain, like the weather tomorrow.

Borislav also gives his students practical advice. "If you feel cold in the classroom, (4) the window yourself — don't wait for me," he tells them. He has one important rule about homework: if a student (5) their homework on time, they lose a small amount of credit. And the rule works both ways — if students (6) questions in class, they usually (7) the next lesson.

One curious student once asked him, " (8) it really get dark earlier in winter?" "Yes, it (9) ," Borislav replied. "The Earth's tilt makes that happen every year — it's simply a fact."

Borislav also teaches a few useful conjunctions. "Plants don't survive (10) they get enough light," he explains, "so always put them near a window." He adds: " (11) the bell rings, everyone should stand up calmly — there's no need to rush." Finally, he reminds his class that fruit isn't ripe (12) it changes colour, so patience is important — in the classroom and in the garden.

Exercises (15 Sets)

All 15 sets practise the Zero Conditional only — matching the 5 parts of Grammar Lab: questions & short answers, conjunctions (unless / as soon as / until), core rules, if vs when & imperatives, and negative conditions.

Tense Writing Practice

Five exercises, 10 sentences each — all mixed tenses.
Put the verb in brackets into the correct tense.

Gerund or Infinitive?

Five mixed exercises. The verb before the gap decides the form.
Key verbs with gerund: enjoy · finish · like · love · hate · avoid · mind · stop · practise · keep · suggest · consider
Key verbs with infinitive: want · need · decide · hope · plan · manage · promise · agree · refuse · expect · offer · learn · forget · remember

Key Word Transformation

How it works: You are given a sentence and a key word. Rewrite the sentence so it means the same, using the key word. The beginning is given — you write the rest. Punctuation counts.
⚠️ Do not change the key word. Check spelling and punctuation before clicking Check.