1, the story of Xiang He has been passed down to this day. If two people struggle for power and profit and only care about their own interests, the country may perish, let alone their own interests, then unity and cooperation will make them all eat grass.

2. During the Three Kingdoms period, Zhang Liao under Cao Cao was happy to stay in Hefei. Sun Quan once sent out 100,000 troops to attack. They were two of the five great generals. They have the same achievements and are famous for their contradictions, but in the face of strong enemies, they can still complement each other, advance and retreat together, and finally defeat the enemy.

One monk carries water to drink, two monks carry water to drink, and three monks have no water to drink.

4. An ant has to move rice, but it can't afford to move around. Two ants came to carry rice, and their bodies were dangling. Three ants came to carry the rice and gently carried it into the hole.

The unity and friendship between Marx and Engels are unmatched by any unity and friendship in the world. Marx admired Engels' talent and said that he was following in Engels' footsteps.