Pollution is a serious problem. Scientists have _______ some good ways to save it.
--_____ you speak Chinese? –Yes,I’ve stayed in China for two years.
I _______ fly a kite with my family.
--- What about ______ to the park? ---Good idea.
1. I like playing _____ piano, but she likes playing ____ tennis.
Please be careful _____ your things from now on.