What does friendship mean? Maybe different people have different ideas. There is no clear answer to this question. Friendship is an eternal theme in literature, and it is also very important in daily life. Friendship is to our life what salt is to dishes. When you are happy, friendship is like icing on the cake; If you are in trouble, friends will surround you and remove obstacles for you. We admire the great friendship between Marx and Engels, which firmly unites them and pushes them forward on the road of exploring and realizing communism.