They were all asleep. of them heard the sound.A. BothB. AllC. NoneD. Neither

问题补充：

They were all asleep. of them heard the sound.

A. Both

B. All

C. None

D. Neither

答案：

A. Both

B. All

(答案→)C. None

D. Neither

解析：考查不定代词。表示三者或三者以上中没有一个人或物，用none of ,故选C。