---Is it good to look up every new word when I come across it in reading? ---No. You ______because you are likely to guess the meaning from the context. A. can’t B. mustn’t C. don’t have to C. ought not to
---We all had a lot of fun at the barbecue yesterday. Pity you weren’t there.
---I really should have gone with you, but I ________ on some remaining problems.