The ability ______ is very important for any speaker.

The ability ______ is very important for any speaker.
A、to hear clearly
B、to be clearly heard
C、to hearing clearly
D、to being clearly heard
【正确答案】：B
【题目解析】：本题测试非谓语动词的用法。动词不定式的被动式做定语修饰“the ability”。