问题描述：
There be句型完全倒装.但不知道为什么后面的动词要加ed
____a certain doubt among the students as to the necessity of the work
A.It existed B There existed C There had D Existed there
There be句型完全倒装 不知道原来的句子是什么样的?
为什么exist要加ed?
再请分析下句子的意思
____a certain doubt among the students as to the necessity of the work
A.It existed B There existed C There had D Existed there
There be句型完全倒装 不知道原来的句子是什么样的?
为什么exist要加ed?
再请分析下句子的意思
问题解答：
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