These four images are simple, clear, concentrated and strong. They are rich, that is, they are not piled up but implicit and have tension, which can induce readers to associate in many ways. These four images materialize and concretize a very abstract "homesickness" and achieve a good artistic effect through "supporting things and expressing feelings".
These images are connected by two simple demonstrative pronouns, "this" and "that", which skillfully integrate the isolated people, events, time, space and sad ends. If there is no distance and connection, it will give people who are lovesick, parting and gathering all day long a strong sound, giving people an unspeakable sadness and joy.
Poetry takes the sequence of time as the longitude and the distance between the two places as the latitude, which has its own fascinating charm and makes people feel infinite sorrow.
Extended information. The whole poem has four sections. On the one hand, poets write poems with the changes of time: childhood-after growing up-later-now, four life stages. On the other hand, the poet takes the space barrier as the characteristics of these four stages: the separation of mother and son when I was a child-the separation of husband and wife when I grew up-the separation of mother and son later-the separation of the wanderer from the mainland now.
The poet found a corresponding word to express his homesickness in four stages of his life: childhood stamps-boat tickets when he grew up-later graves-now straits. From this, we can see that this poem promotes poetic expression layer by layer with the isolation and change of time and space.
Poetry presents the beauty of orderly structure and the beauty of musical rhythm. Pursuing lively and powerful expression in uniform and neat sentence patterns, and perfectly using the phonology of words in appropriate image combinations make poetry have the rhythm of music, full of twists and turns, singing and sighing.
The poet sang the poet's deep attachment to his hometown and motherland with the modern poetic language which integrated the traditional aesthetic characteristics of China.
References:
Baidu encyclopedia-homesickness