You are to learn this poem by Wednesday.
I was to learn this poem by Wednesday.
I had to learn this poem by Wednesday.
I shall have to learn this poem by Wednesday.
He has to learn this poem today as he did not learn it yesterday.
You won’t have to learn this poem.
I did not have to learn this poem.
As he learnt this poem yesterday, he does not have to learn it now.
This week we are to meet with an outstanding scientist.
There was no way out, and he had to pay a fine.
I was to write an essay on Pushkin’s creative activity, and for this I had to reread some of his works which I remembered badly.
I shall have to stay at home these days. The doctor says I am not to go out till my temperature is normal.
Stay here while he is busy. I don’t think you will have to wait long.
The performance was to begin at seven o’clock.
We had to put off the trip as the weather had got worse.
If you want to master a language, you have to read a lot.
According to the new timetable we are to have five English lessons a week.
We decided that the school orchestra was to play in the concert.
Sooner or later you will have to see the doctor.
Next year we are to begin studying astronomy.
To work out a new theory the scientists had to do (perform, carry out) numerous experiments.