Our teacher said to us that the earth _________ around the sun.
–Bill is warm-hearted and works hard. —________ his sister Betty.
–How can I operate this machine? —Well, just refer to the _______.
He threw away all the ______ cigarettes, _______ to give up smoking for the sake of his health.
Mandy, ___ university student from Canada, teaches us ___ history of western art.
He always works hard, but__________, he didn't pass the exam.