Is cancer and sagittarius a good couple?

im not a cancer or sagittarius im a libra but im writing this for my teacher his sign is a cancer and my other teacher is a sagittarius but when they are around each other they look so happy aww so are they a good couple but the thing is my cancer teacher is all about family and my sagittarius teacher is all about adventures and she don;t care about stupid things and she gets jealous alot of other girl teachers feeling on my teacher