Which line in Du Fu's "Spring Hope" uses a contrasting technique to express the poet's concern for his country and his home?

The country is broken by mountains and rivers, and the city is full of spring vegetation.

"The country is broken by mountains and rivers, and the city is full of spring vegetation." The opening chapter writes about what Chun Wang saw: the capital of the country fell, the city was dilapidated, Although the mountains and rivers are still the same, there are weeds all over the place and the trees are green. The word "broken" makes people frightened, and then the word "deep" makes people full of sadness. Sima Guang said: "'The mountains and rivers are there', it is clear that there is nothing left;' The grass and trees are deep, and there is no one around." ("Wen Gongxu's Poetry Talk") The poet here clearly describes the scenery, but actually expresses his feelings, placing his feelings on things and his feelings on the scenery, which creates the atmosphere for the whole poem. This couplet is skillful and mature. Naturally, the poetic mood is overturned. "National destruction" and "city spring" have opposite meanings. The dilapidated ruins of "national destruction" and the prosperous "city spring" are in sharp contrast. "National destruction" continues. "Mountains and rivers are here" have opposite meanings and are unexpected; "City spring" was originally supposed to be a bright scene, but the suffix "deep grass and trees" describes the state of desolation. It is contradictory and another twist. Hu Zhenheng in the Ming Dynasty praised this very much. Lian said: "The duality is not bad, but it changes vertically and horizontally, surpassing the stereotypes, with dark and light colors, and the movements are ingenious.", 1,