题目内容
用括号里动词填空,注意使用适当的语态:
I didn't receive the letter. I think it ________ (must lose) in the post.
答案:must have been lost
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题目内容
用括号里动词填空,注意使用适当的语态:
I didn't receive the letter. I think it ________ (must lose) in the post.