Hello, fellas. In this session we will learn how to use be supposed to.
Be supposed to is used to convey the idea that someone expects something to occur. Be supposed to often conveys expectations about scheduled events or correct procedures.
1) The meeting is supposed to begin at 11:00.
2) The election of the government is supposed to be carried out by secret ballot.
Be supposed to also conveys expectations about behaviour.
You are supposed to park here.
In the past, be supposed to conveys unfulfilled expectations.
She was expected to participate in our discussion last night. (The speaker expected her to participate, but she did not)
Betty Schrampfer Azar, Understanding and Using English Grammar: Third Edition
Cambridge Advanced Learner’s Dictionary – 4th Edition