The computer system suddenly while he was searching for information on the Internet.
John ___ be a basketball player.He’s much too short.
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