Công thức thì QKHT

(+) S + had + V3/ed 

(-) S + had + not + V3/ed 

(?) Had + S+ V3/ed?

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. are standing

DHNB: right now (HTTD)

2. had 

DHNB: last night (QKD)

3. had put 

QKHT+ before + QKD

`color{orange}{~LeAiFuRuiHuiBao~}`