Hi. I am confused about some of the sentences in this lesson

Question

Some sentences seem very similar to "will have" (futur antérrior) and I can't tell the difference. For example:  Apparemment, ils seraient partis ce matin.
Apparently, they would have left this morning.

Selon Tom, elles seraient rentrées chez elles vers 3 heures.
According to Tom, they would have come home around 3. Why would you not say"According to Tom, they will have come home around 3" or "Apparently they will have left this morning"?

Answer

These various sentences require a condition to be met whether implied or not.
If we write "Will have, etc." there is no condition to be met, there is a sense of certainty.
Perhaps there appears to be similarity but the point to bear in mind is the mood implied  --  
certainty or conditional.
Hope that helps.
Alan

Answer

Adding to what Jim said:The futur anterieur uses the future of the auxiliary and is a sort of a "future perfect" - ie. will have left/gone/eaten. - so Ils seront partis ce matin là, or elles seront rentrées chez elles, or je serai arrivé...The conditionnel passé refers to something in the past which might or might not have occurred - ie. would have left/gone/eaten.