Question

虚拟语气 选择题求教

These experts were now fully convinced that the animal ______ a puma.

A.must be B.should have been C.can only be D.could only have been
答案是什么，为什么？说得清楚点追加分数哦

Answer 1

根据课文These experts were now fully convinced that the animal ___was___ a puma.来选
答案 是D 这是对过去情况 的判断
选项A.应该是must have been
选项 B.should have been意思不对 这是虚拟语气 本该是 言外之意 不是
选项 C.can only be应首先排除 时态不对
选项D.是正确答案 could only have been= must have been
这是对过去情况的 肯定判断 只能是、一定是

Answer 2

D
对过去事情的猜测，用【情态动词+完成式】should表示一种责任，故不合适。

Answer 3

D.could only have been a puma可能一定是美洲狮，对过去发生的事情必须用 情态动词+ have+ 过去分词，推测过去发生的事情 要用could have +过去分词

Answer 4

选A 看now fully convinced 现在十分确定the animal must be a puma 这种动物一定就是美洲狮。