A is much longer than B. = A比B长得多。 A is even longer than B. = A比B更长。

Hi Ruby, when used as a comparative, they can be used in the same sentences. The trip to London is even longer than the trip to Paris. The trip to London is much longer than the trip to Paris. The new machine makes even longer sausages than the old machine. The new machine makes much longer sausages than the old machine.

Even longer: longer still Much longer: longer by far I hope that helps ;)

No. They are totally different. Even longer suggests that something used to be long and becomes longer now. Much longer just emphasizes the extent.