13. Dangerous chemicals can be _________ from burning plastics or hairspray containers.
A. freed B. invented C. released D. escaped
14. He finally __________ the decision to go abroad.
A. came up B. came C. came with D. came up with
15. We had a party last night. I .............. spend all morning clearing up the mess.
A. must have B. have been to C. have had to D. have must
16. The smaller the room is, the__________furniture it needs.
A. fewer B. smaller C. more D. less
17. The winners are the first ones __________ a fire.
A. make B. makes C. making D. to make
18. Farmers use the dung of animals for___________ their field.
A. fertilizing B. to fertilized C. fertilized D. fertilize
19. When she _________ her mistake, she apologized
A. was realizing B. did realize C. realized D. has realized
20. The librarian is ___________ for all the books in the library .
A. dutiful B. responsible C. confident D. secure