Hello brokenheart1! ( I love your username, it's so aesthetically pleasing. )
The kind of primary source document that I find most interesting to analyze are diaries, because I like to see someone's perspective on a subject or time period. It can be quite interesting and gives me a first hand look on a matter through someone else's eyes and opinions.
I hoped that helped, I always enjoy getting brainliest when possible!
From Allikat74 :)
The Chinese decided to enter the Korean War on November 25-26, 1950. This was an enormous shock to the American forces, as well as to the United Nations. The United States, and in particular U.S. Gen. Douglas MacArthur, believed that the Chinese would not openly enter the war. When China did provide support to North Korea, the effect was catastrophic on the American forces, leading to a great expansion of the conflict.