I think humour is a vital form of entertainment, ____ it makes us laugh and laughing keeps us healthy.

At the evening party the host said ________ was able to solve the riddle could get a nice present as a reward.

—Jack failed the driving test again.—The question is_____ we can help him avoid making the same mistake.

Scientists say it may be five or ten years___________ it is possible to test this medicine on human patients.

（2014年北京市西城区高三5月二模试题）22. ______ Stephon Marbury is an American, he has become a role model among Beijing basketball fans.