问题
选择题
—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
答案：B
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。