It _____(rain) half a day and I don't think it will last long.

问题描述:

It _____(rain) half a day and I don't think it will last long.

has been raining
雨是从中午下起,到现在还在下,所以用现在完成进行时.
句意:
下了整整一个下午的雨,我认为雨不会再下很久了.