Помогите пожалуйста.Поставьте глагол в Present Perfect1. Our son (learn) how to

Помогите пожалуйста.
Поставьте глагол в Present Perfect
1. Our son (learn) how to read.
2. Doctors (cure) many deadly diseases.
3. Scientists (split) the atom.
4. You (grow) since the last time I saw you.
5. English (become) one of the most popular courses at the university.
6. My English really (improve) since I took private lessons.
7. I think (see) that movie before.
8. He never (travel) by train.
9. Joan (learn) two foreign languages.
10. you (meet) him? - No, I never (meet) him.
11. you (see) that movie? - I (see) that movie twenty times.
12. I think I (meet) him once before.
13. People (travel) to the moon.
14. you (be) to France? - I (be) to France three times.
15. James (not finish) his homework yet.
16. Bill not (arrive) yet.
17. The rain (not stop).
18. Mary (love) chocolate since she was a little girl.
19. She (be) in England for six months.