Question

When products made in factories _____, they are thrown away as garbage.

1. A.
   come to an end
2. B.
   are put to use
3. C.
   are used up
4. D.
   wear out

Answer 1

D
wear out本题中意指（become useless form continued use of wear）用坏，穿破，如：The machine will soon wear out.(这机器即将用坏。)come to and end(结束)，put ... to use(投入使用), use up(用完)， come into use(开始投入使用)。