Suppose and supposed to are used very frequently in British English too. We shall see that suppose has a number of different meanings and uses and that supposed to is different again from suppose.

suppose = think/believe/imagine/expect

In this sense, suppose is often used in requests with negative structures when we hope the answer will be positive:

• I don’t suppose you could lend me your dinner jacket, could you? ~ Sure! When do you need it?
• I suppose it’s too late to see the doctor now, isn’t it? ~ Hold on. Let me see if I can fit you in.
• I don’t suppose I could see the doctor now, could I?~ I can fit you in at 11.30. Can you wait till then?

It is also used in short answers with the same meaning of think/believe/imagine/expect. Note that two forms of the negative are possible here:

• Will Jeremy be at Peter’s this evening? ~ I don’t think/suppose/imagine/expect so.
• Will you try to see Jennifer when you get back? ~ I think/suppose/imagine/expect not.
• Would you be prepared to stay on for an extra week? ~ I suppose/expect/guess so.

Note that suppose here describes a mental or emotional state, and it is not normally used in the continuous form.

Suppose/supposing = what if…?

Suppose or supposing can also be used in a quite different way instead of What if…? to introduce suggestions or to express fears. Compare the following and note that the verb that follows suppose or supposing can be in either present of past tense form:

• We haven’t got strawberry jam for the filling, so suppose / supposing we use(d) raspberry jam, would that be all right?
• Suppose / Supposing I come / came next Thursday rather than Wednesday, will / would that be all right?
• Will these shoes will be OK for tennis? ~ I don’t think so. Suppose / Supposing the court is wet and you slip(ped)?

be supposed to + infinitive = should

Supposed to in this sense means that something should be done because it is the law, the rule or the custom. However, in practice it is often not done:

• I’m supposed to tidy my room before I go to bed at night, but I always tidy it when I get up in the morning instead.
• In Germany you’re not supposed to walk on the grass in the parks, but in England you can.
• I’m supposed to return these books by Friday, but I’m not sure whether I can.

In the past tense, it is used to mean that something was planned or intended to happen, but did not happen. Note that in these examples, we can use should have as an alternative to was supposed to:

• I was supposed to go to Cuba for a conference last year but then I got ill and couldn’t go.
• Wasn’t Tom supposed to be here for lunch? I wonder what’s happened to him!
• I should have gone to Cuba for a conference last year but then I got ill and couldn’t go.
• Shouldn’t Tom have been here for lunch? I wonder what’s happened to him!

supposed to be = generally believed to be

Finally, we can use supposed to be in this sense:

• This stuff’s supposed to be good for stomach cramps. Why don’t you try it?
• The castle was supposed to be haunted, but I had a good night’s sleep there nevertheless!

When you are practising these examples in speech, note that the final d in supposed to is not pronounced. It is pronounced as 'suppose to', but should always be written in its correct form grammatically as supposed to.

If you want to practise using some of these phrases look at our board in the You, Me and Us part of our website.