[Grammar] are to?

Can you say the exact meaning of the following sentence?(with its main structure if possible)
you were to say.and the sentences like this

It seems like you are talking about the modal structure "to be to". It means "to have to do something (typically) by law".
We were to wear uniforms in our school years.

leonardoatt said:

Can you say the exact meaning of the following sentence?(with its main structure if possible)
you were to say.and the sentences like this

Click to expand...

Once again, it would be helpful if you could provide more context: there is an enormous difference between the meanings in these two examples:

I don't know how he'd react if you were to say that.
Why did you disappear?? I told you that you were to say a few words of welcome.

Bennevis said:

It seems like you are talking about the modal structure "to be to". It means "to have to do something (typically) by law".
We were to wear uniforms in our school years.

Click to expand...

It does to have to be 'by law'. Your example sentence sounds unnatural to me. I think what you are trying to say would be more naturally expressed as, "We had to wear uniforms throughout out time at school".

fivejedjons,

I meant to say that we were required to wear uniforms. Which part of my sentence sounds unnatural to you?

I thought "to be" can be used in this context. Here is an example from an article written by a native speaker:
Schools in large cities in 21 states laid down rules that all students were to wear uniforms.
I wrote "We were to wear uniforms in our school years" meaning "we were required to".

Bennevis said:

fivejedjons,

I meant to say that we were required to wear uniforms. Which part of my sentence sounds unnatural to you?

I thought "to be" can be used in this context. Here is an example from an article written by a native speaker:
Schools in large cities in 21 states laid down rules that all students were to wear uniforms.

Reasons Why Schools Should or Shouldn't Use Uniforms | eHow.com
​

I wrote "We were to wear uniforms in our school years" meaning "we were required to".

Click to expand...

The example you gave means that the rules in those 21 states said that students will have to wear uniform from now on (or from the time of the decision).

The other example says that you used to have to wear uniform when you were at school.

These are two different meanings of "were to".

I do understand that those are two different usages of "to be to", but still I don't understand why my sentence sounds unnatural. Here is another example:

For these meetings, we were to wear uniforms of blue blazer and khaki pants.
Travel Buzz: Rotary's Group Study Exchange Program--A Look Back On A Month In Patagonia, Argentina

As far as my sentence, is it "in our school years" that sounds unnatural?

Bennevis said:

As far as my sentence, is it "in our school years" that sounds unnatural?

Click to expand...

It does indeed sound unnatural, but 'were to' is also not natural. 'am/is/are to' (there is no infinitive form ''be to') usually imply that the required action takes place after the requirement is made. This is not necessarily so with 'have to'.

So, it is possible to say both:

We have to wear our uniforms tomorrow......and:
We are to wear our uniforms tomorrow.

Also, both:

The notice said we had to wear our uniforms the next day......and:
The notice said we were to wear our uniforms the next day


However, If we wish to express only that there was an obligation to wear our uniforms and that we did wear them. only the first of these two is possible:

We had to wear our uniforms the next day.
*We were to wear our uniforms next day.

Thanks for that correction! As they say, "Live and learn".