Question

Answer 1

1 Mary has learnt E for 3 years

2 The last time I was in HN was 3 years ago

3 While we were having dinner, the phone rang

4 When I stayed in Da Lat, we came across our professor

3 arrived - had left

4 had gone - studied

5 had been cooking

6 had slept - wouldn't feel

7 put - had already sent

8 got - had forgot

9 had failed

10 arrived - had stopped

11 had attended

12 hadn't met