1.I haven't cooked for 3 years .

-> The last time + S+ Ved/cột 2 + was + time 

-> S+hasn't/haven't + Vpp + for/since + time 

2. How long have you bought that bag ?

-> How long + has/have + S +Vpp + .. ?

-> When + did + S+ V-inf ? ( mk nghĩ đề bạn sai rồi , ở câu gốc bought sai phải là buy mới đúng ) 

3. I haven't seen him for 2 days .

-> S + last + Ved/cột 2 + ... 

-> S+hasn't/haven't+Vpp + .... 

4. I have written blog for 2 months . 

-> S + started/began + to V/V-ing + .... 

-> S+has/have + Vpp + for/since + time 

5.When did you be there ? 

-> How long + has/have + S +Vpp + .. ?

-> When + did + S+ V-inf ?

`1.` I haven't cooked for 3 years

S + has/ have + (not) + V_ed/ V3 + for + khoảng thời gian

`2.` How long have you bought that bag?

How long + has/ have + S + V_ed/ V3?

`3.` I haven't seen him for 2 days

S + has/ have + (not) + V_ed/ V3 + for + khoảng thời gian

`4.` I have written blog for 2 months

S + has/ have + (not) + V_ed/ V3 + for + khoảng thời gian

`5.` When were you here?

When + was/ were + S +...?