—How many students are there in the classroom? —　　　They are all in the lab．A. SomeB. None

问题补充：

—How many students are there in the classroom?

—．They are all in the lab．

A. Some

B. None

C. A11

D. Neither

答案：

A. Some

(答案→)B. None

C. A11

D. Neither

解析：词义辨析。Some一些；None没有人；A11所有人；Neither none 无此用法。句意：教室里有多少学生？根据下文，他们都在实验室。可知没有人，故选B。