would rather + bare inf(Preference (same subject))
I'd rather stay home. / She'd rather not go.
Same subject → bare infinitive.
would rather + subject + past simple(Preference about someone else (present/future))
I'd rather you didn't mention it. / She'd rather we were there.
Different subject → past simple.
would rather + subject + past perfect(Preference about someone else (past regret))
I'd rather you hadn't told him.
Past regret → past perfect.
would sooner + bare inf(Preference (same as would rather))
I'd sooner resign than lie.
Formal/literary alternative to would rather.
it's time / it's high time + past simple(Overdue action (criticism))
It's time he grew up. / It's high time we left.
Past simple even for present/future meaning.
it's about time + past simple(Overdue action (mild frustration))
It's about time they fixed the lift.
Same structure as it's time.
had better + bare inf(Strong advice with implied warning)
You'd better call him now. / You'd better not be late.
No 'to': had better do (not had better to do).
be supposed to + inf(Expectation, arrangement, or rule)
The meeting is supposed to start at 9. / He was supposed to call.
Often implies the expectation wasn't met.
be meant to + inf(Intention or design)
This is meant to be a luxury hotel. / What is this button meant to do?
Interchangeable with be supposed to in many contexts.
may / might well + inf(Strong probability (stronger than may/might alone))
She may well be right. / This might well be the answer.
Well intensifies the probability.