Low-carbon lifestyle is of great benefit to improve the world environment._________can be enjoyed from it until you have a deep understanding of it,however.
I'11 never forget the days _____ I lived in the country with the farmers,_____has a great effect on my life.
Something will have to be done about the air pollution,_____?
Is this the museum _____we visited last year?
Though they are not very sure of the long-term ,all the scientists agree to start_____,all the scientists agree to start the research immediately.
--- I think you'd better type this letter again before Mr Smith sees it. --- Oh, dear! (2008 .江西)