Công thức thì HTHT

(+) S + has/have + V3/ed 

(-) S + has/have + not + V3/ed 

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

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

Công thức thì QKHT

(+) S + had + V3/ed 

(-) S + had + not + V3/ed 

(?) Had + S+ V3/ed?

Công thức thì QKĐ (V: thường)

(+) S + V2/ed 

(-) S + didn't + V1 

(?) Did + S+ V1?

DHNB: ago, last (year, month ...), yesterday, in + năm QK, ...

-------------------------------------------------

1. haven't planned

DHNB: yet (HTHT)

2. Have / learnt

DHNB: yet (HTHT)

3. got / had already arrived

By the time + QKĐ, QKHT

4. Have you been / spent

DHNB: before (HTHT), last year (QKD)

5. found / had just left

6. has changed / came

HTHT + since + QKĐ
`color{orange}{~LeAiFuRuiHuiBao~}`