Stress is natural part of everyday life and there is no way to 【C4】______ it. In fact, it is not the bad thing it is often 【C5】______ to be. A certain amount of stress is vital to provide 【C6】______ and give purpose to life. It is only 【C7】______ the stress gets out of control that it can lead to 【C8】______ performance and ill health.
The amount of stress arsons can withstand depends very much 【C9】______ the individual. Some people are not afraid of stress, and 【C10】______ characters are obviously prime material for managerial responsibilities. Others lose 【C11】______ at the first signs of unusual difficulties. When 【C12】______ to stress, in whatever form, we react both chemically and 【C13】______ . In fact we make choice between "flight and fight" and in more primitive days the choices made the difference 【C14】______ life and death. The crises we meet today are 【C15】______ to be so extreme, but however little the stress, it 【C16】______ the same response. It is when such a reaction lasts long, through continued 【C17】______ to stress, that health becomes 【C18】______ . Such serious conditions as high blood pressure and heart diseases have 【C19】______ links with stress. Since we cannot 【C20】______ stress from our lives (it would be unwise to do so even if we could), we need to find ways to deal with it.
【C1】

A. routine
B. habit
C. principle
D. rule