9. (2018重庆B卷)The environment here becomes better and better. ________ birds are coming back.
A. Thousands of  B. Thousand of
C. Thousands  D. Thousand
9. A【解析】考查数词的用法。句意：这儿的环境变得越来越好。鸟正飞回来。根据语境可知本句中表示概数，故选A。