English Conditionals, Passive Voice, Modals & Reported Speech

English Conditionals: Zero to Third

Zero conditional: If / when / unless + Present Simple → Present Simple or a modal verb. Expresses situations that are always true (situations that are always/generally true).

First conditional: If / unless + Present Simple → Future simple (will), imperative, or modal verb. Expresses what will happen if the condition is met.

Second conditional: If / unless + Past Simple → would / could / might + base form. Expresses hypothetical conditions referring to the present or the future (unlikely to happen).

Third conditional: If + Past Perfect Simple → would have / could have / might have + past participle. Expresses a condition that is impossible because it refers to the past.

Wish Clauses

• wish / if only + Past Simple → Refers to a present situation the speaker is unhappy about.
• wish / if only + Past Perfect Simple → Expresses regret about a past action.
• wish / if only + could / would + base form → Expresses a desire for something to happen in the future.

Passive Voice: Form and Tenses

Formation: Direct object + be + past participle (+ by ...). For indirect object patterns: Indirect object + verb passive + direct object.

• Present Simple: active "uses" → passive "is used"
• Present Continuous: active "is using" → passive "is being used"
• Past Simple: active "used" → passive "was used"
• Past Continuous: active "was using" → passive "was being used"
• Present Perfect Simple: active "has used" → passive "has been used"
• Past Perfect Simple: active "had used" → passive "had been used"
• Future Simple: active "will use" → passive "will be used"
• Modals (simple): active "should use" → passive "should be used"
• Modal perfect: active "may have used" → passive "may have been used"
• Have to / obligation: active "has to use" → passive "has to be used"
• Be going to: active "is going to use" → passive "is going to be used"

Modals and Modal Perfect

Common modals: can, be able to, can't, could, may, might, should, need to, have to, must, mustn't, don't have to, needn't, would.

Modal perfect forms: modal + have + past participle (e.g., may have done, could have gone, should have seen). Example passive modal perfect: "may have been used".

Reported Speech: Tense Changes

When reporting speech (backshifting), verbs typically move one step back in time. Examples with the verb "cooperate":

• Direct Present Simple (cooperates) → Reported: Past Simple (cooperated).
• Direct Present Continuous (is cooperating) → Reported: Past Continuous (was cooperating).
• Direct Past Simple (cooperated) → Reported: Past Perfect (had cooperated).
• Direct Past Continuous (was cooperating) → Reported: Past Perfect Continuous (had been cooperating).
• Direct Present Perfect Simple (has cooperated) → Reported: Past Perfect (had cooperated).
• Direct Present Perfect Continuous (has been cooperating) → Reported: Past Perfect Continuous (had been cooperating).
• Direct Past Perfect Simple (had cooperated) → Reported: Past Perfect (had cooperated) — no change.
• Direct Past Perfect Continuous (had been cooperating) → Reported: Past Perfect Continuous (had been cooperating) — no change.
• Direct Future (will) (will cooperate) → Reported: would cooperate.

Relative Clauses: Defining and Non-defining

Defining relative clauses (essential information): use who, that (people); which, that (objects); when, that (time); where (places); whose (possession).

Non-defining relative clauses (extra information): do not use that; use who, which, where, etc., and separate with commas.

Formal: use phrases like "in which". Informal: you can often use "(which)" or omit formal constructions.

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