CDS English · Grammar
Conditionals and the order of tenses
An if-clause and its main clause must use matching tenses, and two linked events must keep their order in time. Learn three if-patterns and four tense-order rules, and most endings choose themselves.
Why this matters
Conditionals are one of the most tested patterns in CDS sentence completion: the paper gives the if-clause and asks for the result, or the other way round. The 'combine the two sentences' items test the same tense rules from the other side. Marks are lost on endings that sound natural but break the tense pattern.
Concept 1 of 3: The three if-patterns and their inverted forms
An if-sentence has two halves. The if-clause states a condition; the main clause states the result. The tense of the if-clause tells you how real the condition is, and that fixes the tense of the result.
Definition
The terms:
- Clause: a group of words with its own subject and verb.
- If-clause: the half that gives the condition. Main clause: the half that gives the result.
- V3 (past participle): the third form of a verb: gone, done, fared, completed.
- Past perfect: had + V3 (had gone, had planned).
The three patterns:
- Type 1, real or likely: If + present, will/can + verb. If it rains, we will stay in.
- Type 2, unreal now: If + past, would/could + verb. Use were for every subject. If I were rich, I would travel.
- Type 3, unreal past: If + had + V3, would/could have + V3. If he had run, he would have caught the bus.
Two more rules:
- Inversion: drop 'if' and put the helping verb first. Had I known = If I had known. Were he here = If he were here.
- A command or request in the main clause takes the present after if: Let me know if you have news.
- Never put will or would inside the if-clause.
Worked example
Choose the ending: If she had left home earlier, ___ (a) she will catch the train (b) she would catch the train (c) she would have caught the train (d) she had caught the train
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2022 · CDS (II) 2022 — English · Q25Easy
Example 1 · Grammar · Conditionals and Tense Sequence
Directions: complete the sentence with the correct alternative
If you had prepared well,
Will or would inside the if-clause
'If you would won' and 'if you will win' are both wrong. The if-clause takes a present, a past or had + V3. Will and would belong in the main clause.
An extra 'been'
'They would have been won the match' is wrong. Winning is an action the subject does, so Type 3 needs only would have + V3: would have won.
Halves from two different types
'If you had planned the work, you shall have completed it' mixes a Type 3 condition with a result that belongs to no pattern. Find the type from the if-clause, then pick the matching result.
Was in Type 2
Formal English uses were for every subject in an unreal condition: if I were, were he. In the exam, 'was he more honest' reads as a question, not a condition.
Concept 2 of 3: Unless, as long as, in case: conditions without 'if'
Not every condition starts with 'if'. Unless means 'if not'. As long as means 'only on this condition'. In case means 'to be ready, because it may happen'. Each word carries its own condition, so the ending must make sense with that meaning.
Definition
The words:
- Unless = if ... not. Unless you hurry, you will miss the bus = If you do not hurry, you will miss the bus.
- Do not add another 'not' after unless: 'unless you do not hurry' doubles the negative.
- As long as / provided that: on this one condition. The present follows it: You can borrow my bike as long as you return it today.
- In case: as a precaution, before the thing happens. Take an umbrella in case it rains.
The method:
- Replace the word with its meaning (if not, only if, to be ready if).
- Test whether the ending follows logically from that meaning.
- Then check the tense: a condition about the future takes the present, not will.
Worked example
Choose the ending: You may stay out late ___ (a) as long as you phone us at ten (b) as long as you phoned us at ten (c) as long as you will not phone us (d) as long as you cannot phone us
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2021 · CDS (I) 2021 — English · Q104Easy
Example 2 · Grammar · Conditionals and Tense Sequence
Directions: complete the sentence with the correct alternative
Unless you fulfil the essential qualifications _______
A double negative after unless
Unless already means 'if not'. 'Unless you do not work' is a double negative. Write 'unless you work' or 'if you do not work'.
An ending that fights the condition
'Unless you work harder, you will pass' is grammatical but illogical. Replace unless with 'if not' and read it again: if you do not work harder, you will fail.
Will after a condition word
'As long as you will return it' is wrong. After as long as, provided that and in case, a future condition takes the present: as long as you return it.
In case is not if
'In case' is about getting ready before something happens, not about doing it only when it happens. 'In case of' + noun also exists (in case of fire, in case of rain), but the noun must be an event that may happen. 'In case of time' means nothing.
Concept 3 of 3: Tense sequence: time clauses, the earlier past, keeping the given tense
When two actions sit in one sentence, their tenses must show their real order in time. A future event after 'when' takes the present. Of two past events, the earlier one takes had + V3. After a past verb of telling, the reported fact moves into the past too.
Definition
The terms:
- Tense sequence: the rule that the verbs in one sentence must fit together in time.
- Time clause: a clause that starts with when, as soon as, before, after or until.
The four rules:
- A time clause about the future takes the present: I will call you when I reach. Not 'when I will reach'.
- Of two past actions, the earlier one takes had + V3: When we arrived, the film had started.
- After a past verb of telling (said, told, was informed), the reported verb goes into the past: She was told that the shop closed at six.
- When you combine two sentences, keep the tense each one already has unless a rule forces a change. 'Has been waiting' stays 'has been waiting'.
Also:
- When marks a point in time. As, because and since can give a reason, so they do not fit 'She got married when she was 22'.
Worked example
Combine: The guests will arrive at eight. We will serve dinner then. (a) We will serve dinner when the guests will arrive at eight. (b) We will serve dinner when the guests arrive at eight. (c) We served dinner when the guests arrived at eight. (d) We will serve dinner when the guests arrived at eight.
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2023 · CDS (I) 2023 — English · Q101Moderate
Example 3 · Grammar · Conditionals and Tense Sequence
Directions: complete the sentence with the correct alternative
They were informed that the inaugural version of the scheme
Will in a time clause
'You can meet him when he will return' is wrong. After when, as soon as, before and until, a future event takes the present: when he returns.
Had + V3 on both actions
Only the earlier of two past actions takes had + V3. The later one stays in the simple past: When she reached the station, the bus had already left.
Changing a tense you were given
In 'combine the two sentences' items, an option that turns 'has been trying' into 'had been trying' or 'is trying' changes the meaning. It is wrong even if it is grammatical.
When versus as, because, since
'Julia got married as she was 22' says her age was the reason. A point in time needs when.
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Watch out for (12)
- Will or would inside the if-clause→ The three if-patterns and their inverted forms
- An extra 'been'→ The three if-patterns and their inverted forms
- Halves from two different types→ The three if-patterns and their inverted forms
- Was in Type 2→ The three if-patterns and their inverted forms
- A double negative after unless→ Unless, as long as, in case: conditions without 'if'
- An ending that fights the condition→ Unless, as long as, in case: conditions without 'if'
- Will after a condition word→ Unless, as long as, in case: conditions without 'if'
- In case is not if→ Unless, as long as, in case: conditions without 'if'
- Will in a time clause→ Tense sequence: time clauses, the earlier past, keeping the given tense
- Had + V3 on both actions→ Tense sequence: time clauses, the earlier past, keeping the given tense
- Changing a tense you were given→ Tense sequence: time clauses, the earlier past, keeping the given tense
- When versus as, because, since→ Tense sequence: time clauses, the earlier past, keeping the given tense
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