When you play basketball, you ______ hold the ball and run with it.A. mustn’t B. needn’t C. couldn’t
--Who are you _____? -- My mother.
-- _______you watching TV? -- Yes, I _____________.
-- What __________ he do? -- He __________ an actor.
Some students are playing football. _______are doing their homework.
There_____many people in Hong Kong______vacation every summer.