题目内容：
（三） Read the following text and fill each of the numbered spaces with ONE suitable word. Write your answers on ANSWER SHFFT l.
Walking-like swimming，bicycling and running--is an aerobic exercise，(31)___builds the capacity for energy output and physical endurance by increasing the supply of oxygen to skin and muscles. Such exercises may be a primary factor in the(32) ___0f heart and circulatory disease.
As probably the least strenuous，safest aerobic activity，walking is the(33) ___acceptable exercise for the largest number of people. Walking(34) ___comfortable speed improves the efficiency of the cardio respiratory system(35) ___stimulating the lungs and heart，but at a more gradual rate(36) ___most other forms of exercise.
In one test，a group of men 40 t0 57 years of age，(37) ___at a fast pace for 40 minutes four days a week，showed improvement(38) ___to men the same age on a 30 minute，three-day-a-week jogging program in the same period. Their resting heart rate and body fat decreased(39) ___.These changes suggest(40) ___of the important-even vital--benefits walking can(41) ___about.
Walking(42) ___burns calories. It takes 3，500 calories to gain or(43) ___0ne pound. Since a one. hour walk at a moderate pace will(44) ___up 300 t0 360 calories. By walking one hour every other day，you Can burn up a pound—and—a—half monthly，or l8 pounds(45) ___-providing there is no change in your in-take of food. To(46).___weight faster，walk an hour every day and bum up 3 pounds a month，or 36 pounds a year.(47) ___your age，right now is the time to give your physical well-being as much thought as you(48) ___to pensions or insurance. Walking is a vital defense(49) ___the ravages of degenerative diseases and aging. It is nature’s (50) ___of giving you a tune up.
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