题目

—Did you find the missing couple in the mountain yesterday? —No, but we ________ to get in touch with them ever since. A. have tried      B. have been trying C. had tried       D. had been trying 答案：B 解析: 因为ever since是“自那以后(直到现在)”之意，常与完成时连用，又根据but 可知，现在也还在设法与他们取得联系，所以用现在完成进行时。

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