Exercise 1. Put the verbs in brackets in the present perfect tense.
1. I (already / visit) __________ our form teacher in the hospital.
2. John (already / read) __________ the letter from Mary.
3. We (not begin) __________ to learn for the test yet.
4. Nancy (be) __________ to Vietnam several times.
5. They (not start) __________ the project yet.
6. The Greens (be) __________ to many countries in the world so far.
7. We (go) __________ to that village to do volunteer work several times.
8. Our teacher (already / explain) ___________ to us how to use the printer.
9. My pen isn't here any more. Someone (already / take) __________ it.
10. Mai (not finish) __________ her homework yet.