Give two examples of ancient people refining words and sentences.

Birds perch on trees by the pool, and monks knock at the door under the moon. "This is a famous sentence that has been passed down all the time. There is also a story about the word "scrutiny": one day, Jia Dao rode on a donkey and suddenly got the phrase "birds perch on trees by the pool, and monks knock on the moon door" At first, he intended to use the word "push", but later he thought of changing it to "knock" and put his hands on the donkey's back to make a deliberation. Unconsciously, he bumped into Jing and Han Yu's guard of honor and was immediately taken to Han Yu. Jia Dao said something inconclusive in the poem. Instead of blaming him, Han Yu immediately thought for a long time and said to Jia Dao, "It's better to knock." In this way, the two became friends. At first glance, these two poems are a bit confusing. Can the poet even see the birds staying in the trees by the pool at night? In fact, this shows the ingenuity of the poet's conception and his inner pain. Just because the moonlight is bright and everything is silent, the slight knock on the door by the old monk (perhaps referring to the author) will disturb the bird, or cause the bird to disturb people, or the bird will fly out of the nest and turn around and live back in the nest. The author captures this fleeting phenomenon to describe the silence of the environment, the silence in the ring and the unexpected victory. If you use the word "push", of course, there is no such artistic effect.