cleaning
要么改成 clean
要么改成 cleaned
keep sth.adj.是保持某物怎么样的意思,如：keep fish fresh 保持鱼新鲜,keep classroom clean 保持教室干净
cleaned为什么也可?是打扫的意思,但由于 教室是被打扫的,所以要用过去分词 cleaned keep classroom cleaned every day 保持教室每天被打扫