句子結(jié)構(gòu)分析,求大神指點：It was 80 years before Christopher Columbus crossed the ...具體如下：
It was 80 years before Christopher Columbus crossed the Atlantic ____ Zheng He had sailed to East Africa.
A. when B. thatC.afterD.since
答案為什么選B.
D怎么就不對了?
答案解析說是強(qiáng)調(diào)句型,可我把it was that去掉后,句子就是：
80 years before Christopher Columbus crossed the Atlantic,Zheng He had sailed to East Africa.
這句話說的通嗎?我感覺是說不通.80 years before Christopher Columbus crossed the Atlantic作時間狀語感覺怪怪的.如果是80 years ago,我還看得懂.
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求大神指點!