Answer:
1. What do you do on the weekend?
On Friday evening, we went to a party. We slept late on Saturday morning, and then in the afternoon we went shopping. At seven o'clock, some friends came round for a meal. We didn't do much on Sunday, in the evening we just watched TV. What about you?
2. I'll phone you (no preposition) next week on Thursday. It'll probably be in the afternoon, at about 3:00 p.m. OK?
3. I don't see my parents much. (no preposition) Christmas, usually and on the summer holidays.
4. On November 9th, 1989, the Berlin Wall was opened. For the first time in the late twentieth century, Germans could go from West to East Berlin without travel restrictions.
:)