What role does the second couplet of Lu You's poem Spring Rain in Lin 'an play in the whole poem?

Lin' an in the early spring

Author: Lu You

In recent years, officials are interested in a thin layer of gauze. Who will let me take a bus to Kyoto to visit this bustling city?

Living in a small building and listening to the falling spring rain, you will hear the sound of selling apricots in the depths of the alley early in the morning.

Slowly spread out small pieces of paper sideways, every word is organized, carefully boil water and tea under the sun window, skim it and try to taste famous tea.

Oh, don't sigh that the dust in Kyoto will stain the white clothes, and there is still time to return to the mirror house in Lake Ubak.

In case you don't understand, let me also say the first sentence:

The first couplet expresses the helplessness of the world and the waste of being a guest in Beijing in the form of questions, and expresses the mind directly. The mood of the whole poem reaches its climax at the beginning.

Therefore:

1, couplets have the function of connecting the preceding with the following, inheriting the strong feelings of grief and indignation, and making the feelings gradually fall back.

2, couplet points out "poetic eye", which is also a famous sentence of Lu You, and the language is fresh and meaningful.

3. Zhuan Xu used the technique of borrowing scenery to express his feelings, and used music scenes to set off his sadness. "Listening to the wind and rain all night" shows that the poet stayed up all night, showing his mood ups and downs, and his worries about state affairs came to his eyebrows with the rain.