Perfect tense

Perfect tense is used for describing a past action’s effect on the present.

The pattern of present perfect tense
(+) S + have/has + verb 3 (been) +object
(-) S + have/has + not + verb 3 +object
(?) Have/has + S + verb 3 +object

Examples:
(+) I have been here for 20 minutes.
(-) I have not learn English since three years ago.
(?) Has he awoke from his bed?

Adverbs used:
- Once
- This week
- Twice
- Since Monday
- Lately
- Many times
Past perfect tense is a kind of tense that is used t describe an action or an event that started in a certain time in the past and completed or finished till certain time in the past too.

The pattern:
(+) S + had +verb 3 +complement
(-) S + had not +verb 3 +complement
(?) Had+ S + verb 3 +complement

Examples:
(+) They had been at school before at 06.30a.m.
(-) I had not slept for a this when I met my cousin.
(?) Had he studied music for a year when I began it?

Adverbs used:
- One
- Twice
- From 1995 to 2000

Future perfect tense is used to describe an action or events that started in the past and finished at the future.

The pattern:
(+) S + shall/will + have +verb 1 (been) +…
(-) S + shall/will + not +have + verb 1 (been)+…
(?) Shall/will + have +verb 1 (been) +…

Examples:
(+) We shall have arrived at Bandung by Monday.
(-) They will not have been at school by the end of this week.
(?) Will you have been a police by next year?

Adverbs used:
- By Sunday
- Next week
- Next month
- Next year
- The end of this week
- The end of this month