10-20............................................................

`10,` I last met my aunt when I was 10 years old.

`11,` She hasn't worked with foreigners before.

`12,` She has cried for two hours.

`13,` We have chatted on the phone since it began to rain.

`14,` We have known each other since we were at university.

`15,` She hasn't phoned her parents for 3 weeks.

`16,` We haven't gone to this restaurant for a long time.

`17,` How long have you had this laptop?

`18,` I haven't joined such an exciting party before.

`19,` The last time I heard from her was many years ago.

`20,` The last time the children was taken to the park was in 2012.

`@` Cấu trúc thì QKĐ -> QKHT

`a,` S + last + Ved/V2 + O + time

= The last time + S + Ved/V2 + O + was + time

= It's + time + since + S + (last) + Ved/V2 + O

= S + has/have + not + Vpp + O + for/since ... 

`b,` This/It is the first time + S + has/have + Vpp

= S + has/have + not + Vpp + O + before

= S + has/have + never + Vpp + O + before

`c,` S + started/began + to V/V-ing + O + when/in/on/at...

= S + has/have + Vpp + O + for/since + ...

`d,` When + did + S + V-inf + O?

= How long ago + did + S + V-inf + O?

= How long + have + S + Vpp + O ?