______ is some doubt that ……[A.There B.it]并说明原因谢谢

______ is some doubt that ……[A.There B.it]并说明原因谢谢
______ is some doubt that ……[A.There B.it]并说明原因谢谢

______ is some doubt that ……[A.There B.it]并说明原因谢谢
A,这是there is some doupt + that+从句的句型,相关短语还有：there is no doupt that...是毫无疑问的
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A 存在某种猜测

选A，there be 句型

关於doubt的句型你可以这样判断
有疑问 用there
没有疑问 用it/there 都可以