One is a "small stamp", which symbolizes the author's homesickness when he was a teenager. A mother cares about her son, who misses her.
The second song is "A Narrow Boat Ticket", which symbolizes the homesickness of the lovers in the author's youth. This is the yearning and yearning between young men and women.
The third part is A Short Grave, which symbolizes the author's nostalgia for life and death in middle age. This is an unforgettable miss that can only be buried in the bottom of my heart and cannot be passed on between two people. Although it is only a stone's throw away from the ancient tomb, it is so far away.
The fourth song is "A Shallow Strait", which symbolizes the author's nostalgia for his old country in his later years. Although the strait is "shallow", the feelings of the motherland are unfathomable. Moreover, the author's emotion is deep, progressive step by step, and unforgettable. The connotation and realm of the author's "homesickness" has been deepened and promoted with his own maturity and the development of the times, from personal affection and affection to patriotism on both sides of the strait. This makes Nostalgia have a distinct color of the times.