give the correct form of the verbs in the present perfect:
1.Tom<see>this film before.
2.I<finish>my excercise already.
3.They<live>here since 1990.
4.My father<just wash>his car.
5.The students<discuss>the question recently.
6.Mary<never,be>to Ha Noi
7.We <know>each other for 5 years.
8.So far we<learn>five lessons.
9.We<be>pen pals for a long time.
10.They<stay>here since last week.