the report that the missing plane has been found was untrue
问题描述：
the report that the missing plane has been found was untrue
为什么主句时态是过去时,而从句是现在完成时
答
消失的飞机在报道之前已经发现了.所以用完成时.报道已经发出去了,所以是过去时
其实has been 用 had been更好,因为过去的过去用过去完成时