Which expression method is used in the last two sentences of sending Wei Er off?

The first and last two sentences use the expression method of imagination.

2. Expand knowledge:

1. Appreciation of the original poem: Farewell to Wei 2

The fragrance of oranges and pomelos in the river tower is intoxicating, and the river wind brings rain into the cool boat.

I recall you far away in the Xiaoxiang month, and worry about listening to the ape's dream.

2. Introduction to the work: "Farewell to Wei Er" is a poem by Wang Changling, a poet of the Tang Dynasty. The last two sentences imagine that Wei Er heard the cry of an ape in his dream and was unable to fall asleep. On the surface of the poem, the poem describes the sadness after the separation of friends, but in fact it is the author's sighing emotion when bidding farewell to Wei Er. The whole poem combines reality and reality, and with the help of imagination, it expands the space of expression, expands the artistic conception, and deepens the theme. It has a hazy beauty and is quite unique in artistic conception.

3. About the author: Wang Changling, a poet of the Tang Dynasty. His courtesy name was Shaobo, a native of Jingzhao Chang'an (now Xi'an, Shaanxi Province). One is from Taiyuan (now part of Shaanxi). In the fifteenth year of Kaiyuan (727), he passed the Jinshi rank and was awarded the title of Wei of Sishui (today's Xingyang County, Henan Province). He then moved to Jiangning to be the Prime Minister, and was called the King of Jiangning in his later life. In his later years, he was demoted to captain of Longbiao (now Qianyang, Hunan). Because he returned to his hometown after the Anshi Rebellion and left Bozhou, he was killed by the governor Lu Qiu Xiao. His poems are good at Qijue, and his poems on frontier fortresses are powerful and high-spirited; he also has works in which he is indignant about current affairs and depicts palace resentments. The original collection has been lost. The Ming Dynasty compiled "Wang Changling Collection".