根据短文内容，判断对错。

A swallow (燕子) and a duck are going to see their friends. On the way they meet a river in front of them.

The swallow says, "We should fly across the river."

"No, we should swim across the river," says the duck.

They have a quarrel (吵架) . And both of them are very angry with each other. An old sheep comes up to them and says. "Swallows can't swim. Ducks can't fly. You should think more of others (其他人).