—Tom must be at home because the light in his house is on.—He ____ be at home, because I saw him playing basketball on the playground.A. must B. can’t C. mustn’t
---What's ________ wrong with you? --- I have ______ sore throat.
--Why is she at Xiao Ying’s home? --_________ they are friends.
We are ________ a school trip..
---When is Christmas? --- It’s _____ December 25.
---Is Nancy doing her homework? -----___________.