There were signs here and there,_____visitors to look out for ____rocks.

题目

There were signs here and there,_____visitors to look out for ____rocks.
A warning,fallen
B warning,falling
c warned,falling
d to warm,fallen
为什么

答案

答案是 B warning,falling
warning短语直到句末,是现在分词短语作定语,其解释说明作用.falling是现在分词,意思是“正在落下的”,作rocks的定语.