(2009·全国卷Ⅰ)What do you mean, there are only ten tickets？There________be twelve.

––__________ I smoke here?–– No, you __________.

－I’d like to help the homeless people in the earthquake. －You ________ join a volunteer group. 

You’d better take another flight to New York , for the AA 505 Flight ______ have been cancelled. But you should call the airport to make sure. 

Please do not feed the fish; they _____ die if they eat too much.