题目内容：

We must help ______(keep) our enviroment clean.

优质解答

keep/ to keep
两个答案都可以

追问：

My mother missed _____ in the country. A to live B live C living D lived 我看今晚要下雨 It _______ ______ _____ that it will rain tonight.

追答：

C It looks as if that it will rain tonight.