Mastering English Grammar: A Comprehensive Overview

Indirect Style

Changes in verb tenses when using indirect style:

• Present simple to past simple
• Present continuous to past continuous
• Past simple to had + past participle
• Past continuous to had been + past participle
• Present perfect simple (has/have + past participle) to had + past participle
• Present perfect continuous (has/have been + past participle) to had been + past participle
• Past perfect simple (had + past participle) does not change
• Past perfect continuous (had been + past participle) does not change
• Future simple (will) to would

Changes in Modals:

• Can to could
• May to might
• Must/have to do not change

Changes in Words and Expressions:

• Now to then
• Today to that day
• Tonight to that night
• Yesterday to the previous day
• Last week to the previous week
• A month ago to the previous month
• Tomorrow to the following day
• Next week to the following week
• Here to there
• This to that
• These to those

Passive Voice

• Present simple: is/are + past participle
• Present continuous: is/are being + past participle
• Past simple: was/were + past participle
• Past continuous: was/were being + past participle
• Present perfect simple (has examined): had been + past participle
• Past perfect simple (had examined): had been + past participle
• Future simple: will be + past participle
• Modals: should be + past participle
• Modal perfects (must have examined): must have been + past participle
• Have to: has to be + past participle
• Be going to: is going to be + past participle

Causative

Subject + have/get + direct object + past participle

Modals

• Can (ability or possibility)
• Could (past of can)
• May (possibility, but in the future)
• Might (synonym of may, possibilities in present and future)
• Will (future)
• Should/ought to (obligation or recommendation, reflects an opinion about what is correct)
• Must (indicates an obligation, prohibition, or necessity. "Have to" can also be used)
• Would (used to state a preference and to ask for something politely)

Modal Perfects

• Must have: used to express a logical conclusion about something that happened in the past.
• May have/Might have: used to express possibility in the past. The use of these two modals also expresses uncertainty.
• Can't have: used in a similar way to "must have", but in the negative form. We can use "can't have" when we are quite sure that something did not happen or was not true in the past.
• Could have: also used to express that something was possible in the past but did not actually happen.
• Should have/ought to have: used when something did not happen, but it would have been better if it had happened.
• Would have: conditional sentences

Conditional Sentences

• 1st Conditional: if + present simple - subject + will + rest of sentence
• 2nd Conditional: if + past simple - subject + would + verb
• 3rd Conditional: if + past perfect - subject + would have + past participle