(单选题)

—Is the letter from your sister?
—Yes. But she ______ the letter herself, because she doesn’t even know one word.

A.needn’t have written

B.can’t have written

C.might not have written

D.should not have written

参考答案：B

参考解析：

考查情态动词表推测。句意：“那封信是你妹妹寄的吗？”“是的。但信不可能是她自己写的，因为她一个字也不认识。”根据后半句she doesn’t even know one word可知，前半句应表示对过去事实的否定推测，应使用can’t have done，意为“不可能做某事”。故选B。

知识点：

—Is the letter from your sister?—Yes. But she ______ the letter herself, because she doesn’t even know one word.