Summer vacation should be shorter so that students can have more frequent breaks throughout the school year fact or opinion ?

I believe this would be an OPINION

Explanation:

As much as this could be a fact, there is not only NOT enough information given to make it one, but also, the person stating this is reasoning from only their prospective; thus making it an opinion

Lamb to the slaughter" is an innocent is being sacrificed for the needs of another. In this case, Mary is that lamb. Heavily pregnant and a devoted wife, her needs are being sacrificed to her husband's desire for a divorce. Mary is the one who is going to have to suffer because of his decision, and she has done nothing (as far as we know) to deserve this fate.