共用题干
Exercise
Whether or not exercise adds___1___the length of life,it is common experience that a certain___2___of regular exercise improves the health and contributes a feeling of wellbeing.
Furthermore,exercise___3___involves play and recreation,and relieves nervous tension and mental fatigue in so doing,is not only pleasant but beneficial. How much and what kind of exercise one should___4___merits careful consideration. The growing child and the normal young man and young woman thrill with the exhilaration of strenuous sports.They fatigue to the___5___of exhaustion but recover promptly with a period of rest. But not so with___6___of middle age and beyond. For them moderation is___7___vital importance. Just how much exercise a person of a given age can safely take is a question___8___to answer. Individual variability is___9___ great to permit of generalization.
A game of tennis may be perfectly safe for one person of forty but folly for another. The safe limit for exercise___10___ on the condition of the heart,the condition of the muscles,the type of exercise,and the regularity with which it is taken.Two general suggestions,however,will___11___ as sound advice for anyone.The first is that the condition of the heart and general health should be___12___ periodically by careful, thorough physical examinations. The___13___is that exercise should be kept below the point of physical exhaustion.
What type of exercise one should___14___depends upon one's physical condition. Young people can safely enjoy vigorous competitive sports,but most older persons do better to limit themselves to less strenuous activities. Walking,swimming,skating are among the sports that one can enjoy and safely participate___15___throughout life. Regularity is important if one is to get the most enjoyment and benefit out of exercise.
3._________
A: which
B: where
C: when
D: why