Some people viewed the findings with caution, noting that a cause relationship between passive smoking and cancer remains ________.
A) to be shown
B) to have shown
C) to have been shown
D) being shown
为什么a?
这句子是被动的,先排除BD
然后to be done是指什么什么将被做
to have been done 有已经的意思
联系句意,所以就选A了
然后to be done是指什么什么将被做
to have been done 有已经的意思
联系句意,所以就选A了
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第1个回答 2009-06-08
remain to do 是固定短语
句子意思应该是“消极的抽烟与癌症之间的关系有待被察看”
所以应该是被动
句子意思应该是“消极的抽烟与癌症之间的关系有待被察看”
所以应该是被动
