问题描述:
In the past three years ,he ____the country twice.
A.visited B.is visiting C.had visited D.has visited
选什么呢,为什么?C和D怎么判断?
A.visited B.is visiting C.had visited D.has visited
选什么呢,为什么?C和D怎么判断?
问题解答:
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