1.
1 usually walks
2 Do you speak
3 has already booked
4 I have been learning
5 Have you ever met

2.
1 c
2 b
3 c
4 d
5 a

3.
1 They launched the first spaceship in 1975.
2 I looked at the clock and realized that it had broken.
3 They had finished the interview by that time.
4 When did you visit your granny last?
5 We had left before the rain started.

4.
1 It was raining heavily when she left the house.
2 The fire was destroying most the buildings while he was sleeping.
3 When they travelled around the country they were seeing a tornado.