643.David threatened ______ his neighbour to the police if the damages were not paid.
A.to be reported
B.reporting
C.to report
D.having reported
644.________ many times,he finally understood it.
A.Told
B.Telling
C.Having told
D.Having been told
643.答案是C;短语threaten to do sth.扬言要干某事。
644.答案是D;主语与tell之间是被动和完成的关系，故用having been done来表示被动和完成。
