6̉̉. in
7. in
8 . in
9. on
10. about

1. in
2. down
3. at
4. on
5. of
6. of
7. of
8. for
9. as
10. for
11. of - for

1.we give each other presents .in..Christmas
2,Don't sit .down..the floor
3,I'm going away at...the end of January
4,I met Tom .on.the street yesterday
5,They sent me a cheque.of..$50

6.There has been some decrease..of..military spending this year
7.Nobody knows what the cause.of..the explotion was
8.Do you think we'll find a solution.for..this problem?
9.Have you ever read any books .as..Mark Twain?
10.It's unreasonable .for..you to expect her to love you first