Chia dong tu cau : John and Mary..................(not contact) each other for a long time

`Đáp` `án:` haven't contacted 

DHNB: for a long time (HTHT)

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Công thức thì HTHT

(+) S + has/have + V3/ed 

(-) S + has/have + not + V3/ed 

(?) Has/Have + S+ V3/ed?

S số ít, he. she, it + has

S số nhiều, I, you, they, they + have

DHNB: before, since + mốc thời gian, for + khoảng thời gian, yet, already, just,....