Safety in school has been of great concern because of frequent reports about accidents _______ students got injured or killed while in school .

Must I hand in my homework now?—No,you__.You can hand it in tomorrow.

His father ________ in the factory since he was twenty.

I __________the poor rabbit, but I didn’t have the right drugs with me at that moment.

Look! A book is on the floor. Whose is it?—It ______be Rick’s. It has his name on it.