Jogging has become the most popular individual sport in America．Many theories have been put forward to explain the popularity of jogging．The truth is that jogging is a cheap, quick and efficient way to achieve physical fitness．

The most useful sort of exercise is exercise that develops the heart, lungs, and circulatory （循环）systems．If these systems are fit, the body is ready for almost any sport and for almost any sudden demand made by work or emergencies．Running trains your heart and lungs to deliver oxygen more efficiently to all parts of your body．It is worth noticing that this sort of exercise is the only kind that can reduce heart disease, the number one cause of death in America．

The only equipment that is needed is a good pair of shoes．Physicians advise beginning joggers not to run in tennis or gym shoes．A good running shoe will give the knee and ankle（脚踝）more stability（稳定性）．Wearing good shoes will prevent the foot, ankle and knee injures and will also enable the wearer to run on different surfaces．

No other special equipment is needed; you can jog in any clothing you want, even in your street clothes．Many joggers wear expensive, flashy warm–up suits, but many people just wear a simple T-shirt or jog in last year’s clothes．In cold weather, several layers（层） of clothing are better than one heavy sweater or coat．If joggers are wearing several layers of clothing, they can add or take off layers as conditions change．

    It takes surprisingly little time to develop the ability to run．The American Jogging Association has a twelve–week program designed to move from a fifteen–minute walk （which almost anyone in reasonable health can manage） to a thirty-minute run．A measure of common sense, a physical examination, and a planned schedule are all it takes．

1．The main purpose of this passage is to         ．

A．discuss jogging as a physical fitness program
B．describe the type of clothing needed for jogging

C．provide scientific evidence of the benefits of jogging

D．promote some shoes for jogging

2．Which of the following is the only special equipment that joggers need?

A．Good shoes．  B． Street clothes．    C．Expensive suits．    D． Warm-up trousers．

3．The most useful kind of exercise is exercise that         ．

A．trains the body for weight lifting
B．enables a person to run ahead with great power

C．is both beneficial and inexpensive

D．develops the heart, lungs, and circulatory systems

4．We can conclude from this passage that         ．

A．because of jogging, heart disease is no longer an American problem
B．jogging can be harmful if the runner is not properly prepared
C．warm–up suits are better than T-shirts for jogging
D．jogging is bad for your heart and lungs