问题
选择题
The chairman’s speech ______ the radio when I turned it on.
A．was broadcast on
B．was being broadcast on
C．was broadcasting in
D．broadcast over
答案
答案：B
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。