5．Research findings show we spend about two hours dreaming every night，no matter what we____
during the day.
A．may be doing B．could have done C．must have done D．might have done
解析：句意：“研究调查结果表明，我们每天晚上花费大约两小时作梦，不管我们白天做过什么。”no matter what...是让步状语从句，用“must have done”一定……(判断)和“could have done”“本可，本能”(没做)，不合句意，答案是D(“might have done”“也许”)。
答案：D
6．The newcomers found it impossible to________themselves to the climate sufficiently to make permanent homes in the new country.
A．suit B．adapt C．fit D．match
解析：句意：“新来的人们发现使他们自己完全适应这儿的气候，在这个新的国家长期住下是不可能的。”考查词义辨析；suit强调“合乎口味，性格，颜色，款式”；fit强调“尺寸，型号”；match强调“相配，相称。”答案B，最合句意。
答案：B
