Japanese professor Yoji Kimura believes laughter is a weapon that in healthy doses（剂量） can end the world’s wars. To measure it, the expert on communications has invented a machine to chart out laughter—and a new unit of “aH” to calculate it.
“We have found that children laugh more freely, releasing（释放）10 aH per second, which is about twice as much as an adult,” Kimura, a professor at Kansai University in the western city of Osaka, told reporters. “Adults tend to calculate whether it’s appropriate to laugh and under those restraints（克制） they eventually forget how,” he said.
“Laughing is like a restart function on a computer. Laughing freely is very important in the course of human development,” he said.
Kimura, who believes in “a change from a century of wars to a century of humor and tolerance,” has studied the science of laughter for decades in Osaka. In his theory, human laughter is produced in four emotional stages. “I believe there is a circuit（回路） in the human brain that creates laughter,” Kimura said confidently.
To measure laughter, he attaches sensors on the skin of a tested people’s stomach, particularly the diaphragm（横膈膜）, and detects muscle movements. “I have a theory that humor detected in the brain gets directly released through the movement of diaphragm,” he said. By checking the movement of the diaphragm and other parts of the body, it will be possible to see if a person is only pretending to laugh while also telling different types of laughter, Kimura said.
Kimura wants to make the measuring device as small as a mobile phone and possibly market it as a health and amusement device. Kimura said he planned to present his findings this summer to the US-based International Society for Humor Studies, adding that he looked forward to looking at differences in laughter internationally.
According to the passage, Professor Yoji Kimura _____.

A．thinks banning weapon can end wars in the world

B．has put his machine calculating laughter into market

C．has been studying laughing for many years

D．is an expert in people’s health problem

Why do adults laugh less freely?

A．Because they are busy with their work.

B．Because they are affected by some factors.

C．Because they use computers too often.

D．Because they don’t think it good to laugh much.

The measuring device of Yoji Kimura _____.

A．has functions of a mobile phone

B．can make people laugh more

C．can recognize different kinds of laughter

D．will be popular in the international market soon

The passage mainly tells us something about _____.

A．how to measure laughter	B．Yoji Kimura and laughing
C．laughing as much as possible	D．a device that is made to measure laughter