Present Perfect Tense and Continuous Tense

Indicates an action that started in the past and has just finished
Assertive:
- Subject + has/have + verb (past participle) + object
- Example: She has written a letter.
Negative:
- Subject + has/have + not + verb (past participle) + object.
- Example: She has not written a letter.
Interrogative:
- has/have + subject + verb (past participle) + object?
- Example: Has she written a letter?
Interrogative Negative:
- has/have + subject + not + verb (past participle) + object?
- Example: Has she not written a letter?
Key words: up to now, still now, so far, at the moment ago, this morning, this month/year, for, since, yet, never, always, so far, times, many times, lately, recently, already, just now, ever, never, yet, recently

Shows an action that started in the past and is still continuing
Assertive:
- Subject + has/have + been + verb (present participle) + object.
- Example: She has been writing a letter
Negative:
- Subject + has/have + not + been + verb (present participle) + object
- Example: She has not been writing a letter.
Interrogative:
- has/have + subject + been + verb (present participle) + object?
- Example: Has she been writing a letter?
Interrogative Negative:
- has/have + subject + not + been + verb (present participle) + object?
- Example: Has she not been writing a letter?

Used to denote scientific facts, universal truths, and actions done daily
Assertive:
- Subject + verb (base form) + s/es + object.
- Example: She writes a letter.
Negative:
- Subject + does not + verb (base form) + s/es + object.
- Example: She does not write a letter.
Interrogative:
- Does + subject + verb (base form) + s/es + object?
- Example: Does she write a letter?
Interrogative Negative:
- Does + subject + not + verb (base form) + s/es + object?
- Example: Does she not write a letter?
Key words: Every day, month, week, year; always; sometimes; never; frequently, daily, seldom, rarely, habitually, occasionally, generally, seldom

Expresses an action taking place at the time of speaking
Assertive:
- Subject + is/am/are + verb (present participle) + object.
- Example: She is writing a letter.
Negative:
- Subject + is/am/are + not + verb (present participle) + object.
- Example: She is not writing a letter.
Interrogative:
- is/am/are + subject + verb (present participle) + object?
- Example: Is she writing a letter?
Interrogative Negative:
- is/am/are + subject + not + verb (present participle) + object?
- Example: Is she not writing a letter?
Key words: look, see!, here, watch, now, at this time, on this time, in this moment, at present, listen, still, don’t disturb.

Refers to actions that happened at a specific point in the past
Assertive:
- Subject + verb (past tense) + object.
- Example: I used to go for a walk.
Negative:
- Subject + did not + verb (base form) + object.
- Example: I did not wish to talk to about that matter.
Key words: that day, ago, previous day, yesterday, once upon a time, in the past, day before yesterday, few years back, last (year/week/month/night)

Shows an action that was ongoing at some time in the past
Assertive:
- Subject + was/were + verb (present participle) + object.
- Example: She was writing a letter.
Negative:
- Subject + was/were + not + verb (present participle) + object.
- Example: She was not writing a letter.
Interrogative:
- Was/were + subject + verb (present participle) + object?
- Example: Was she writing a letter?
Interrogative Negative:
- Was/were + subject + not + verb (present participle) + object?
- Example: Was she not writing a letter?

Describes an action completed before a certain time in the past
Assertive:
- Subject + had + verb (past participle) + object.
- Example: She had written a letter.
Negative:
- Subject + had + not + verb (past participle) + object.
- Example: She had not written a letter.
Interrogative:
- Had + subject + verb (past participle) + object?
- Example: Had she written a letter?
Interrogative Negative:
- Had + subject + not + verb (past participle) + object?
- Example: Had she not written a letter?
Key words: after, before, by, as soon as, when

Denotes an action that began before a certain time in the past and continued until a specific time in the past
Assertive:
- Subject + had + been + verb (present participle) + object.
- Example: She had been writing a letter.
Negative:
- Subject + had + not + been + verb (present participle) + object.
- Example: She had not been writing a letter.
Interrogative:
- Had + subject + been + verb (present participle) + object?
- Example: Had she been writing a letter?
Interrogative Negative:
- Had + subject + not + been + verb (present participle) + object?
- Example: Had she not been writing a letter?

Used to express actions that will happen in the future
Assertive:
- Subject + will/ shall + verb (base form) + object.
- Example: She will write a letter
Negative:
- Subject + will/shall + not + verb (base form) + object.
- Example: She will not write a letter.
Interrogative:
- Will/shall + subject + verb (base form) + object?
- Example: Will she write a letter?
Interrogative Negative:
- Will/shall + subject + not + verb (base form) + object?
- Example: Will she not write a letter?
Key words: tomorrow, next + future time, in the future, soon, coming year, day after tomorrow, after some days/weeks/years.

Expresses an ongoing action in the future
Assertive:
- Subject + will/shall + be + verb (present participle) + object.
- Example: She will be writing a letter.
Negative:
- Subject + will/shall + not + be + verb (present participle) + object.
- Example: She will not be writing a letter.
Interrogative:
- Will/shall + subject + be + verb (present participle) + object?
- Example: Will she be writing a letter?
Interrogative Negative:
- Will/shall + subject + not + be + verb (present participle) + object?
- Example: Will she not be writing a letter?