I asked him whether he had done all the work himself ________ whether he had had any assistance

The success of Shenzhou-X spacecraft that the Chinese people have taken the historic step in the advance of climbing up to the peak of the world’s science and technology.

Since the man had no choice but to fight back, we’d better _________ him.

It is dangerous ____ you ______ a close look at the tiger in the zoo.

ericans would prefer to keep their problems themselves,and solve their problems ______ themselves