单选题When products made in&nbs

问题补充：

单选题Whenproductsmadeinfactories_____,e to an endB.are put to useC.are used upD.wear out

答案：

D解析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)。