Modals for obligation and advice	

Be aware that in some of the examples there are other ways to express the same ideas, both with and without modal auxiliary verbs. 

You keep forgetting to pay your phone bill. If you don't pay it today, they will cut you off. 

I must remember to pay the phone bill today. 	You have recently put on 5 kilos. Remind yourself to stop eating cheesecake. 

I must stop eating cheesecake	
Your colleague Ron is retiring after 20 years working in your office. You think it would be a nice idea to get him a leaving present. 

I think we ought to / should get Ron a leaving present.	Explain to a new colleague that if the photocopier breaks down, the rule is that you must make out a report. But no one does. 

You're supposed to make out a report if it breaks down… 	
You are explaining to a new member of staff the rules about eating in the office. No eating at your desk - but everyone does. 

You're not supposed to eat at your desk, but everyone does. 	Explain to a foreign visitor what is necessary for a trip to Macau (Passport: yes; visa: no; change money : no) 

You have to take your passport, but you don't have to get a visa and you don't need to change any money as you can use your Hong Kong money there.	
You are in a meeting. You think that it is very important that you all reduce the amount of paper you waste. 

We really must do something to reduce the amount of paper we waste. 	You are very happy. Normally it is necessary for you to work on Saturday mornings. But for the next month it is not necessary. 

I don't have to work on Saturday mornings for the next month. 	
Explain that you will not come to the party - it is necessary for you to work late. 

I can't come to the party as I have (got) to work late. 	Your friend doesn't feel well. He says he's got chest pains and can't breathe properly.

You'd better go to the hospital straight away	
Explain the rules relating to dress in your company to an interview candidate.  (suit and tie: not necessary;  casual clothes: yes;  short trousers: no)  

You don’t have to wear a suit and tie. You can wear casual clothes but short trousers aren’t allowed.	You see your six-year-old son playing with a lighter.

You mustn’t play with lighters.	
A newcomer to Hong Kong tells you she spent a lot of money on a new camera in Tsim Sha Tsui. Tell her she went to the wrong part of town - Mong Kong is much cheaper.

You should have gone to Mong Kok – it's much cheaper.	You're hungry and looking for a nice snack. You see a delicious-looking cake in the fridge and are about to take it. You brother knows it's Amy's (your sister's), cake and that she's been looking forward to eating it. He says:

You'd better not eat that – it's Amy's.	
You do a small favour for a colleague. The next day she brings you an expensive present. You say, 'That's very kind of you but you…

…needn't have bought me a present.	You're telling your friend about a trip to a museum. She asks if it was expensive. You explain that was not necessary to pay as it is was included in the price of the tour.

We didn't need to pay anything…