【题目】It’s reported that a subway system will be _____ use in 2020 in Taiyuan.
A. put off B. made of
C. put into D. made into
在线课程【答案】C
【解析】
考查动词短语辨析。句意：据报道，一套地铁系统将于2020年在太原投入使用。A. put off推迟；B. made of由...制成；C. put into 投入；D. made into制成。be put into use“被投入使用”符合句意。故C选项正确。