The fireman succeeded in saving all the people in the house on fire, _______they knew they were in great danger themselves.
—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.
She promised to ______ at the meeting but she didn’t ______.