______,weshouldsleepatsleepatleast8hoursaday,butinpract...

问题详情：

______, we should sleep at sleep at least 8 hours a day, but in practice we sleep less than that.

A. In fact    B. In theory

C. On average    D. In particular

【回答】

B

知识点：词组 短语

题型：选择题