l. 
1. to get lost
2. to turn dull grey 
3. to share a tent with somebody
4. to smash into something
5. to set up tents
6. to talk to someone
7. to lie in a tent

2.

1. The sun had appeared in the sky  before they left the campsite.
2. When my father got home after work I had already gone to bed. 
3. I had been learning English at school for two years before I passed the exam.
4. The lesson had already lasted for fifteen minutes   when I entered the classroom.
5. I had known her for five years before we became real friends.
6. My teacher said that I had missed two classes  since the beginning of the second term.