【2013河南】—George, how can you prove the earth is round? —I can't, sir. ______ I never said it was.
——I don’t know ______ watch this is. Do you know? ——It might be Gao Lei’s.
What a nice day! We should go sightseeing ________ watching TV in the hotel.
——Must I come to see you again? ——No, you _________.
He has done _________ to improve his English.
It’s ______ cold today, so I have still finished ______ homework.