What do you mean by shaking your head?

"Cao Cao shook his head", and "straight" means: insist on doing something.

"Cao Cao shook his head" means that Cao Cao kept shaking his head after hearing it. Hearing this, Cao Cao has a strong sense of negation, which is the negation of the first instinct, and there is no room for it, so he will "keep shaking his head."

The process of Cao Chong's elephant-weighing

1. First, catch the elephant on the boat and mark its diving position along the water surface. Catch the elephant ashore, and then put stones on the boat until the boat sinks to the place where the line is drawn. 3. Weigh the stones on the boat. The weight of the stones is the weight of the elephant.

Cao Cao asked, "Who can weigh this elephant?" Some said, "You have to build a large scale and cut down a big tree to make a scale." Some said, "Even if it is a big scale, who has the strength to lift it?" Others said, "One way is to kill the elephant, cut it into pieces and weigh it." Cao Cao shook his head.

Cao Chong, the son of Cao Cao, is only seven years old. He stood up and said, "I have an idea. Drive the elephant to a big ship and see how much the hull sinks. Just draw a line beside the boat along the water. Then the elephant was driven ashore, and the stone was loaded on the boat until the boat sank to the place where the line was drawn. Then weigh the stones on the boat. Elephants are as heavy as stones. "

Cao Caoxiao nodded. He told people to do as Cao Chong said, and sure enough, he weighed the elephant.