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 HTĐ (V: thường)

S số ít, he, she, it 

(+) S + Vs/es

(-) S+ doesn't + V1 

(?) Does +S +V1?

S số nhiều, I, you, we, they

(+) S + V1 

(-) S+ don't + V1 

(?) Do + S+ V1? 

DHNB: always, usually, sometimes, often, never, seldom,....

Công thức thì HTTD 

(+) S + am/is/are + Ving 

(-) S + am/is/are + not + Ving 

(?) Am/Is/Are +S +Ving? 

DHNB: now, right now, (!), at present, at the moment,.....

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. Cleans

DHNB: once a week (HTD)

2. Is cleaned

DHNB: once a week (HTD)

S + am/is/are + V3/ed: bị động

3. Was painted

DHNB: yesterday (QKD)

S + was/were + V3/ed: bị động 

4. Be typed

S + should be + V3/ed: bị động 

5. Is making

DHNB: tonight (HTTD)

6. Has been missing

DHNB: for three days now (HTHTTD)

S + has/have + been + V3/ed

7. Will be sent

DHNB: tomorrow (TLĐ)

S + will be+ V3/ed: bị động 

8. Was shocked 

DHNB: yesterday (QKD)

9. Has taught

DHNB: since 1989 (HTHT)

10. Will be published 

DHNB: next year (TLĐ)

11. Didn't find

DHNB: last week (QKD)

12. Hasn't been / bought

HTHT+ since+ QKD 

13. Haven't written 

DHNB: for a year (HTHT)

14. Did/ spend

DHNB: last year (QKD)

15. Invented/ was invited 

DHNB: in 1878 (QKD)