639.It rained heavily in the south,_______ serious flooding in several provinces.
A.caused
B.having caused
C.causing
D.to cause
640.He had a wonderful childhood,_____ with his mother to all corners of the world.
A.travel
B.to travel
C.traveled
D.traveling
639.答案是C;现在分词表示结果状语。
640.答案是D;主语he与动词travel之间是主动关系，故用过去分词作条件状语。
