B. with
C. on
D. at
31.The atmosphere _______ certain gases mixed together in definite proportions.
( C )
A. composes of
B. is made up
C. consists of
D. makes up of
32.He didn’t have time to read the report word for word. He just
_______ it.
( A )
A. skimmed
B. observed
C. overlooked
D. glanced
33.He _______ at the thought of seeing the pretty girl again.
( B )
A. cheered off
B. cheered up
C. cheerful
D. cheered on
34.Knowing first aid (急救) is _______ to saving lives.
( C )
A. cure