―There will be ___________ to treat 10 people to lunch.―Sounds __________.
---Hi. Lucy! What’s wrong with you? You look so worried.---I have many problems to solve, but I don’t know ___________ first.
---I find the more we study, the more difficulty we have ________ out Maths problems.---Oh, I agree with you. Maths is more and more difficult.
---What a mess(杂乱)! Tony, you should ___________ your things to keep the room clean.---OK, Mum! I’ll do it at once.
---Where was your sister at this time yesterday evening ? ---She was writing an e-mail ______ I was watching TV at home.
--- Would you like black or white coffee? --- Well, I ______ coffee ______ milk.