posted by Pete .
I went to parent-teacher conferences, and it was not what I expected.
I have learned that at parent-teacher conferences not all the parents show up.
Are those sentences correct?
In the first sentence, you have "conferences" (plural) and then "it" (singular) to refer to "conferences." They don't match. You have a pronoun-antecedent mis-match here.
The second sentence is fine.