1/ Because he had a toothdache.

2/Because I didn't have enough time.

3/ Because he has seen it already.

4/Because she is honest and polite.

5/ Because she didn't complete his homework.

6/ Because I missed the last bus.

1.He went to the dentist beucause he has a toothache.

2.I didn't take part in volunteer programs because I didn't have enough time.

3.He wants to go and see the film because he has seen it already.

4.She is popular in school because she is honest and polite.

6.I went home late last night because I missed the last bus.