It's raining so heavily that the water in the river can be seen _____.

问题描述:

It's raining so heavily that the water in the river can be seen _____.
A.rise B.raise C.rising D.raising

答案是C.
rise 是一个不及物动词;而raise是一个及物动词,后面必须接宾语.
句型:see sb.doing sth.