1.In all the world, there (be) are only 14 mountains that (reach) reach above 8,000 meters.

2.He sometimes (come) comes to see his parents.

3.When I (come) came, she (leave) had left for Dalat ten minutes ago.

4.My grandfather never (fly) has never flown in an airplane, and he has no intention of ever doing so.

5.We just (decide) have just decided that we (undertake) would undertake the job.

6.He told me that he (take) would take a trip to California the following week.

7.I knew that this road (be) was too narrow.

8.Right now I (attend) am attending class. Yesterday at this time I (attend) was attending class.

9.Tomorrow I’m going to leave for home. When I (arrive) arrive at the airport, Mary (wait) will be waiting for me.

10.Margaret was born in 1950. By last year, she (live) had lived on this earth for 55 years.

11.The traffic was very heavy. By the time I (get) got to Mary’s party, everyone already (arrive) had already arrived

12.I will graduate in June. I (see) will see you in July. By the time I (see) see you, I (graduate) will have graduated.

13.I (visit) visited my uncle’s home regularly when I (be) was a child.

14.That book (be) has been on the table for weeks. Haven't you (not read) read it yet?

15.David (wash) is washing his hands. He just (repair) has just repaired the TV set.
16. Have You (be) ____been______here before? Yes, I (spend) _____spent_____ my holidays here last year.