Do an experiment _______ me, please.[ ]
A. at
B. on
C. in
B
There is no _________ that the Chinese people will present to the world a successful, splendid and unforgettable exposition（博览会）.
A．belief
B．doubt
C．possibility
D．need
空气的热湿处理包括（）。
A、加热
B、冷却
C、加湿
D、减湿
