22.If we know more about _______causes the problem, we may take measures before it is _______late.
____ wide spread of H1N1 is _____ challenge for the whole world. Confidence, cooperation and responsibility are keys to overcoming it.
Would you like to ______ us? We are going to _____ the school’s 20th anniversary celebration.
Great Expectations is __ in England in the early 1800s.
–I’m glad to be offered the job. Shall I start tomorrow?– ______. See you tomorrow.
Yesterday I was invited to the dinner at .