I ought to / had to phone the workers three times before I got an answer.
had to
You ______ to touch it if you don’t know what you're doing.
oughtn't
They must/have tidy up when they've finished
must
Be careful, you mustn't / don't have to touch anything electrical.
mustn't
Do you think I must / should ask Harry for help?
should
The work ____ to be really good quality.
has / need
You _______ help us but it would be nice.
needn't
They ____ to finish everything before last June.
had
I don't need to / needn't to read the instructions again.
don't need to