The difference between passing away and passing away

after seven days and seven nights of hunger strike, Wang died suddenly. ..... On the eighth day of the first month of the 21st year of Kangxi, Gu Yanwu, who was seventy years old, slipped and fell to the ground while going out to mount a horse. The indomitable patriot died in the early morning of the next day, ending his hard and diligent life. (Wang Zhenyuan's Gu Yanwu and the History of the Ming Dynasty)

Abnormity died suddenly. To die suddenly, especially to die of illness.

Zhou Deqiu's younger brother followed his brother's instructions and sent the money to Ji Hanxiong. Ji Hanxiong knew that he had died suddenly, and he couldn't help crying. (Xiao Fuxing's "Life as a Distinguished Person") Due to poverty and lack of medical care, coupled with poor daily necessities, Xue Qin finally passed away on New Year's Eve. (Wu Xinlei's Cao Xueqin XIII)

Death: Farewell. Farewell to the world forever. To die politely (especially for people you admire). Usually with a solemn color.

For this reason, the authorities didn't hold a memorial service for him, and this famous calligrapher died with deep injustice. (Zhang Tongwu's Beyond Love) Less than a year later, I got the bad news of his death. (Ke Ling's Salute to the Pioneers —— Preface to Selected Essays of A Ying)

Also called "Passing away".

While the National Congress was being held, there was unfortunate news that Sun Yat-sen, the great forerunner of the democratic revolution, passed away in Beijing on March 12th, 1925. (Chapter 4 of Historical Draft of Beiyang Warlords by Lai Xinxia and others)

Both refer to death. Often used as a predicate, sometimes used as an attribute.