- Be supposed to = be expected to; be scheduled
Let's go to the movies tonight?
I'm sorry I can't, I'm supposed to study math tonight.
- Be surprised at = be taken aback by; express surprise at; be astonished.
Marina was surprised at her daughter's behavior at the party last night.
- be used to: be familiar with; be accustomed to
Sarah is used to waking up early in the morning.
You work a lot everyday. Do you fell very tired?
No, I think I'm used to working hard.
Attention: the expression be used to is followed by a verb with ing.