2. Guanyinyan and Nanyue
be tasteless
4.i don't know
5. Battle of Guandu,
First of all, Yuan Shao is too arrogant and willful to listen to good opinions, such as Tian Zhou.
As soon as Xu Gou defected to Cao Cao, he offered a plan to burn grain and grass, and pointed out the place where Yuan Shao kept the grain and grass.
Three surrendered to Cao Cao.
Battle of red cliff
Cao Cao started his army, but the northern soldiers didn't learn to swim. After fighting in the south, they haven't adapted.
Strategic mistakes of two tandem ships
After unifying the north, Cao Cao was complacent and credulous of Huang Gai's false surrender. 6.i don't know. 7. I don't know