I’d like to travel by air _________ it usually costs a lot of money.
Jenny and Mary are good friends. _________ often help each other.
May is the _________ month of a year.
The story happened_________ March, 2014.
I didn’t have _____ to say, so I said _____.
—Do you know about Yuan Longping? —Only a little. But Chinese people are proud of the man ______ hybrid rice is famous.