Meaning of "should"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Dear teachers,

Please tell me the meaning of “should” in:
a. We should arrive before dark.
b. The roads should be less crowded today.
c. The letter should be on its way to you.
d.I should have finished by Friday.

Thanks
Quoc

2

Hi,

They all suggest ‘ought to’ in the sense of that’s what would be expected.

Alan