从A. B. C. D.四个选项中，选出可以填入空白处的最佳选项。
21. --- What terrible weather! It _________ for more than a week!
--- The rain season will last about a month.
A. rains B. will be raining C. rained D. has been raining
22. He called the police for help, _______ that the problem was more than he could deal with.
A. having been realized B. to realize C. realizing D. realized
