Sure, here are the completed sentences:

1. A: We went to New York last month.
B: Where did you stay?
A: With some friends.

2. A: I was late this morning.
B: What time did you arrive?
A: Half past nine.

3. A: I played tennis this afternoon.
B: Did you win?
A: No, I lost.

4. A: I had a nice holiday.
B: Good. Where did you go?
A: To the mountains.

5. A: We came home by taxi.
B: How much did it cost?
A: Ten pounds.

6. A: I'm tired this morning.
B: Did you go to bed late?
A: No, but I didn't sleep very well.

7. A: We went to the beach yesterday.
B: Did you have a nice time?
A: Yes, it was great.

8. A: The window is broken.
B: How did it happen?
A: I don't know.