11.A. for B. to C. at D. with
10.A. serious B. harmful. C. dangerous D. helpful
9. A. by B. across C. through D. against
8. A. For B. Until C. When D. Since
7. A. easy B. small C. large D. light
6. A. found B. invented C. called D. bought
5. A. takes B. helps C. gets D. brings
4. A. in B. to C. by D. over
3. A. also B. but also C. too D. either
2. A. twenty-first B. twenties C. twelfth D. twentieth