1.He hasn't gone skateboarding before

-This/It is the first time+S+have/has+V3=S+haven't/hasn't+V3+before

2.She has learnt to drive for 1 month

-S+started/began+to V/V-ing+khoảng thời gian+ago=S+have/has+V3+for+khoảng thời gian

3.We have walked since It started to rain

-S+started/began+to V/V-ing+mốc thời gian/when+QKĐ

=S+have/has+V3+since+mốc thời gian/QKĐ

4.I haven't had my hair cut since I left high school

-S+haven't/hasn't+V3+since+mốc thời gian/when+QKĐ

=S+last+V2+since+QKĐ

5.We haven't talked for a long time

-For+khoảng thời gian(VD:2 WEEKS,4 MONTHS,...)

-SINCE+MỐC THỜI GIAN

`1` He hasn't gone skateboarding before

`2` She has learnt to drive for 1 month

`3` We have eaten since it started to rain

`4` I haven't had my hair cut since I left high school

`5` We haven't talked for a long time

`-` CT :

This/It + is + time + S + has/have + V-II

`=` S + has/have + not + V-II + before

S + started + V-ing + time + ago

`=` S + has/have + V-II + for + time

S + began + V-ing + when + ....

`=` S + has/have + V-II + since + ....

S + last + V2/V-ed + when +...

`=` S + have/has + not + V-II + since + ...

$baoyen.$