That light rail transit line(轻轨), __ _in July 2009 and ___ in 2012, will be China’s longest light rail transit line in history.
See who’s there! ____ it be Mary?
“Can I take it away?” “You ___ better not.”
“Let’s go to the library, shall we?” “____”
“Do you have to leave now? ” “I’m sorry, but I really ____.” A. can’t B,have C.should D.must
He ___ be in the garden.He must be in the room. ‘