$\text{1. are - reach.}$

$\text{2. comes.}$

$\text{3. came - had left.}$

$\text{4. has never flown.}$

$\text{5. have just decided - would undertake.}$

$\text{6. would take.}$

$\text{7. was.}$

$\text{8. am attending - was attending.}$

$\text{9. arrive - will be waiting.}$

$\text{10. had lived.}$

1. ln all the world, there are only 14 mountains that reach above 8,000 meters.

2.He sometimes comes to see his parents.

3.When I came, she had left for Dalat ten minutes ago.

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

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

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

7.I knew that this road was te narrow.

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

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

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