问题补充:
单选题Thechairman’sspeech______theradiowhenIturnediton.A.was broadcast onB.was being broadcast onC.was broadcasting inD.broadcast over
答案:
B解析考查时态以及介词的用法。从when I turned it on可知,前句应该用同进行时有关的时态;broadcast与speech之间存在被动关系,“通过收音机”可以用over/on the radio。“通过电视”则说:on TV(无冠词),“通过报纸”through newspapers。