be supposed to vs have to

Hi,

Supposed to: Be supposed + infinitive is used to say what people have to do (or not do) according to the rules or the law, or about what is (not) expected to happen.

Catholics are supposed to go to church on Sundays.
We're supposed to pay the Council Tax at the beginning of the month.

The source: Practical English Usage (page 563)

Can we use 'have to' in the second sentence intead of 'supposed to'? I think we can but we may not do it for the first one.

Thanks.

We don't have to pay our council tax at all. However, we should be aware that there are consequences if we don't. However, I think the "supposed to" in your second sentence refers to the date it is expected to be paid, rather than the fact that it simply should be paid. I would expect something to come after your example sentence, indicating that paying at the beginning of the month isn't always the case. For example:

We're supposed to pay our council tax at the beginning of the month but some of us have arranged to pay it on the 20th of the month.

Thanks for the answer but I still feel confused. Is it wrong to put 'have to' in those sentences?

Catholics have to go to church on Sundays.
We have to pay the Council Tax at the beginning of the month.

ademoglu said:

Thanks for the answer but I still feel confused. Is it wrong to put 'have to' in those sentences?

Catholics have to go to church on Sundays.
We have to pay the Council Tax at the beginning of the month.

Click to expand...

They're correct. To have to conveys a higher level of obligation than to be supposed to. "We are supposed to pay the Council Tax" means that a rule urges payment on a given date; if we have to pay the tax, we understand that we'll suffer a fine or some other consequence if we don't pay.

emsr2d2 said:

We don't have to pay our council tax at all.

Click to expand...

We certainly do have to pay it, but it doesn't have to be at the beginning of the month.