When you run, you put force that is equal to three times your body weight on your feet. The human foot contains twenty muscles（肌肉）. This means that there is a lot that can go wrong when you run.
Most sports have some kind of running or jumping. So experts（专家） at many shoe companies work hard to design good sport shoes. First, a designer enters a plan for a shoe into a computer. Engineers then improve the design. A second computer designs a model for the shoe. Then a few pairs are made. Next, the shoe is tested.
Different kinds of sports shoes are made for different uses. Some are made to help marathon runners save energy during a race. Some are made for the stop-and-go kind of running tennis players. But all sport shoes have one thing in common: they are designed to help people’s feet comfortable during sports. Today, nearly every sport has its own special shoe designed for just the kind of running that sport requires.
The first in making a new shoe is to ______.

A．make a computer	B．design a shoe model
C．test several pairs	D．put a design plan into a computer

Why are good sport shoes welcome to people?

A．Because they help to change body weight.

B．Because they help to develop leg muscles.

C．Because they are both good and cheap.

D．Because they are comfortable to wear.

What is NOT talked about in the passage?

A．The number of the bones of a human muscle.

B．The effect of shoes upon sports.

C．The materials （材料）of sport shoes.

D．The design for a shoe model.

Different kinds of sport shoes _______.

A．are designed for people of the different weight.

B．meet the needs of different sportsmen.

C．are made in different shoe companies.

D．are of the same price.