Key I
1.b 2.c 3.a 4.b 5.a 6.a 7.c 8.c 9.a 10.a 11.b 12.b

Key II

1. run
2. drop
3. to do
4. take
5. complaining
6. to have found
7. sharing
8. to talk about
9. not to gossip
10. you ought to be told / you should be told

Key III

1.b 2.b 3.a 4.a 5.b 6.a 7.c 8.b 9.a 10.b