If you are in the zoo, remember not to touch or go near the animals. Although some of the animals are cute, you _________ leave them alone. 

—Must I clean my room now, Mum?—_______. You can do it tomorrow.

I have never heard______.

— Look at the boy playing basketball on the ground. Is it George?— It ________ be him. He told me he would play basketball after class, but he’s not sure.

—Do you know where Mary is? I couldn’t find her anywhere.—Well . She        have gone far—her coat’s still here.