题目内容：
共用题干Exercise
Whether or not exercise adds to the length of life,it is common experience that a certain amount of
regular exercise_______(51)health and contributes a feeling of well-being. Furthermore,exercise
________(52)involves play and recreation（娱乐）,and relieves nervous tension and mental fatigue in so
__________(53),is not only pleasant but beneficial.
How much and what kind of exercise one should
_________(54)merits careful consideration.The grow-
ing child and the normal young man and young woman thrill（兴奋） with strenuous（剧烈的）sports. They
fatigue to the__________(55)of exhaustion but recover promptly with a period of rest.But not so with those
of middle age and beyond. For them moderation is_________(56)vital importance.
Just how much exercise a person of a given age can safely take is a question hard to__________(57).In-
dividual variability is too great to permit generalization.A game of tennis may be perfectly safe for one per-
son of forty but folly（愚蠢）for another. The safe_________(58)for exercise depends on the condition of
the heart,the condition of the muscles,the_________(59)of exercise,and the regularity with which it is
taken. Two general suggestions,however,will__________(60)as sound advice for anyone.The first is that
the___________(61)of the heart and general health should be determined periodically by careful,thorough
physical examinations. The other is that exercise should be kept__________(62)the point of physical
exhaustion.
What type of exercise one should___________( 63)depends upon one's physical condition.Young
people can safely enjoy competitive sports,but most older persons do better to limit themselves to less strenuous
___________(64).Walking,swimming and skating are among the sports that one can enjoy and safely
___________(65)in throughout life.Regularity is important if one is to get the most enjoyment and benefit out
of exercise.
_________(56)
A:to
B:below
C:of
D:on
参考答案：
答案解析：