If he had not joined the army, he ________ alive now.
—Turn off the TV, Jack. ____your homework now? —Mum, just ten more minutes, please.
. —What do you think we can do for our aged parents? —You ________ do anything except to be with them and be yourself.
His lack of professional knowledge _______for the failure of the experiment.
Not believing their eyes, the visitors on the spot _______ the flying plane, doing some most difficult and dangerous tricks in the sky.
Many festivals are held _______ our ancestors for their contribution to the world.