---Michael,           do you go swimming?--- Twice a week.

------I am not going swimming tomorrow afternoon.------___________. I have to clean up my bedroom.

____________of the twins passed the exam because they worked hard at their lessons. 　

－Are the keys yours?－No, they aren’t _____. I think they’re Jason’s.

—Are these books ________?   —No, they are not mine. They belong to _____.