Pollution is a serious problem. Scientists have to _____ some good ways to save it.A. come up with B. come on C. come out
--I’m sorry I ______ my exercise book at home. ---Don’t forget _______ it to school tomorrow, please.
--- I lost my bike yesterday and had to walk home. --- __________.
Is Zhalong one of the world’s ________?
Now the Chinese government has made laws ______ the people ______ in some public places like schools and hospitals.
Sandy’s drawing is ________ than ________.