1: Thì quá khứ đơn:
Form: 
(+): S + V_ed/V_C2 + O
(-): S + did + not + V + O
(?): Did + S + V + O?
Ex: 
(+): She watered the flowers yesterday
(-): He didn't do his homework yesterday evening
(?): Did they build that house?

2: Thì hiện tại hoàn thành:
Form: 
(+): S + have/has + V_pp + O
(-): S + have/has + not + V_pp + O
(?): Have/Has + S+ V_pp + O?
Ex:
(+): She has done her homework for an hour
(-): I haven't watched that film before
(?): Has Tom gone to the library yet?

* Quá khứ đơn (Past Simple Tense)

Công thức

(+) S + V_ed + C

(-) S + didn't + V + C

(?) Did + S + V + C?

Egs:

(+) I visited my grandparents last year

(-) She didn't collect stamps in 2016

(?) Did your mother make craft?

* Hiện tại hoàn thành (Present Perfect Tense)

Công thức:

(+) S + have/has + V_ed/P.P + C

(-) S + haven't/hasn't + V_ed/P.P + C

(?) Have/Has + S + V_ed/P.P + C?

Egs:

(+) I have eaten seafood since last night

(-) He hasn't done his homework.

(?) Have you learned English before?

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