There is a man and a cow. What is an idiom?

Don't train cattle and sheep

Idiom explanation: Don't let cattle and sheep trample on it. Metaphor is love.

Replace this one with another.

Interpretation of idioms: Yi: substitution. Replace cattle with sheep. Replace this one with another.

Close to death

Idiom explanation: It is a metaphor for a dying person.

Small gain gain

Idiom explanation: throw away the sheep and get the cow. Metaphor loss is small, gain is big.