Mr. Green is said _____ an experiment to prove the new method of solving the problem when young.
You can’t complain of being lonely _______ you don’t make any effort to meet people.
Our country are working even harder now to _______ the gap between the developed countries and ours.
“Drive-ins” have large parking lots ______ customers are served in their cars by waitresses.
Although it _________ in the desert most of the year, people still live there.
He narrowly escaped _________ in a car accident caused by careless driving.