This computer is of good quality. If it ___________ break down within the first year, we would repair it at our expense.

— I’ll tell Mary about her new job tomorrow. — You ______ her last week. 

 —Why aren’t they here yet?—They_____ the bus.

 Thanks to my teacher's valuable help, otherwise I ________ my college entrance exam.

We ___have hurried all the way to the airport—the flight was called off because of the foggy weather.