1. She has read a book for two hours

    She has read 55 pages so far.

2. She has travelled for three months.

    She has travelled to ten countries.

3. He has been playing tennis since he was 11.

    He has won the national championship four times.

4. They have made films since they left college.

    They have made over ten films since they left college.

5. How long has he grown trees?

    How many trees has he grown?

6. When did she start doing her exercises? (từ start k dùng trong htht do nó chỉ xảy ra trong đúng 1 thời điểm)

    How many exercises has she done?

Chia thì htht do hdong đã và vẫn đag xảy ra, chia thì hthttd để nhấn mạnh về thời gian diễn ra của sự việc.

Xin ctlhn

1 She has read a book for two hours vì two hours thì ta dùng for `to` HTHT.

   She has read 55 pages so far. vì so far nên ta dùng HTHT.

2 She has traveled for three months. vì three months thì ta dùng for `to` HTHT.

   She has traveled to ten countries so far. vì so far nên ta dùng HTHT.

3 He has been playing tennis since he was 11. vì là một mốc thời gian ta dùng since `to` HTHT.

   He has won the national championship four times. vì là một khoẳng thời gian ta dùng HTHT.

4 They have made films since they left college. vì dùng since `to` HTHT.

   They have made over ten films since they left college. vì có since nên chia HTHT.

5 How long is he growing trees? 

   How many trees is he growing?

vì là thì HTTD.

6 When is she start doing her exercises? 

   How many exercises is she doing?

vì là thì HTTD.