—Was it there _______ you were away to see your friend off?—I’m not sure . But when I got back, it was gone.
If you try to learn too many things at a time at the beginning, you may _______.
The war made _______ impossible for the scientist to go on with his research.
There _______ a temple on the side of the mountain, didn’t there?
Our school covers an area of 400 mu, which is _______ as yours.
The experts advise _______ our army _______ modern weapons.