.—Was _________________ problem solved? —We were trying to think of _________________ way out, but it was difficult to find one.
—There ______ be anybody in the classroom, for the lights are off. —I’ll go and check.
Chinese students usually spend ______ the students of the US studying in their free time.
. She has a strong belief that she will ______ her country to take part in the Olympic Games.
With all his efforts, ______ he made such great progress.
______ is even more important is that water began to appear on the earth’s surface.