How long have you _____________ Teresa– For three years by now. Our wedding anniversary is coming next week.

I can’t give up smoking, doctor.—For your health, I’m afraid you ________.

There is no possibility ______ all the students can pass the college entrance examination.[ ]

This math question is too difficult. Can you help me__________

ited States signed up on Friday forthe 2010 Shanghai World Expo, _________ it the last major country to join theevent．