The poem that uses contrast is

2. "Flowers and birds make sorrow this spring", and the poet uses flowers and birds to compare the depth of "sorrow". There is also a couplet in Du Fu's Spring Hope. This couplet is written by means of contrast, and the effect of comparative art is briefly commented.

Petals fall like tears, and lonely birds sing their sadness.

On the whole, birds and flowers are a happy scene; However, here, the singing of birds and the fragrance of flowers only constitute the poet's sadness of going to the frontier. The contrast between Flowers and Birds and Border Worry is to set off border worries from the opposite side. By using the method of contrast, taking flowers and birds as entertainment objects, write the feelings of "feeling the time" and "hating parting".