A. storing B. protecting
C. watching D. remembering
15. Statistics______in the claims of dvertisers, in opinion polls, and in reports of business trends and cycles.
A. has appeared B. appears
C. appear D. appearing
16. If governments stopped adopting trade policies, the world_______an economic condition called free trade.
A. can have B. would have
C. will have D. may have
17. If our_____is correct, the spacecraft should reach the moon on Monday.
A. calculation B. composition
C. communication D. vision
18. One of the first metals put______by early human beings was copper.
A. into use B. for use
C. in use D. to use