单选题
If individuals (are awakened) (each time as) they begin a dream phase of sleep, they are likely to become irritable (even though) their total amount of sleep (has been) sufficient.
【正确答案】
B
【答案解析】each time as 改为 each time。each time是名词短语，意思是“每当，每次”，在句子中可以起连词作用，引导时间状语从句，不与as连用。可以这样用的还有一些名词短语和副词，如：every time，next time，the minute，the instant，the moment，directly，instantly，immediately等。