Safety in school has been of great concern because of frequent reports about accidents _______ students got injured or killed while in school .
________ do you clean your kitchen?- Twice a week.[ ]
_____ do you see your grandparents?— Once a month.[ ]
Here is the knife. You can ask your mother ___the apple for you.
About 20 firemen were killed in the fire which broke ______in Yueyang, Hunan Province last week.[ ]