Chinese in senior high school: how to understand the "expansion of time and space" in poetry? For example, Pan Lang in Jiuquanzi, does his dream have time to go? thank you

"Looking back at the tide, the Manchu people fought for the river. I suspect that the sea is empty and drums are beating all around. Xiang Tao, the frolic in the frolic, stands upright and keeps the red flag wet. I don't look at my dreams more, but I am still chilling. "

"Long memory" means that people often think of the spectacular sight of people going out of the city to watch the high tide of Qiantang River. The sentence "Don't come" expresses the status quo, and the spectacular scene can only be reproduced in the dream now, writing the content and status quo in the dream. It is precisely because of "past", "present" and "dream" that different time and space are reflected, which is "time and space expansion"