By the time Jack returned home from England，his son ________ from college.(2011·辽宁)
A．graduated B．has graduated
C．had been graduating D．had graduated
In the last few years thousands of films ________ all over the world.
A．have produced B．have been produced
C．are producing D．are being produced
— Alvin，are you coming with us?
—I'd love to，but something unexpected ________.
A．has come up B．was coming up
C．had come up D．would come up
—I remember you were a talented pianist at college.Can you play the piano for me?
—Sorry，I ________ the piano for years.(2012·湖南)
A．don't play B．wasn't playing
C．haven't played D．hadn't played
—Look！Somebody ________ the sofa.
—Well，it wasn't me.I didn't do it.(2012·江西)
A．is cleaning B．was cleaning
C．has cleaned D．had cleaned
Daniel's family ________ their holiday in Huangshan this time next week.
A．are enjoying B．are to enjoy
C．will enjoy D．will be enjoying
