問題詳情

For some time now, medical scientists have noted an alarming increase in diseases of the heartand circulation among people who smoke cigarettes. It has been 9 that the presence ofnicotine in the bloodstream causes blood vessels to contract, thus slowing circulation, a conditionwhich 10 leads to hardening of the arteries. As the arteries stiffen, 11 blood reaches thebrain, and the end result of this slowdown is a cerebral hemorrhage, commonly referred to 12a stroke. 13 , nicotine in the bloodstream reduces the ability of the hemoglobin to releaseoxygen, resulting in shortness of 14 , thus causing the person to breathe more rapidly. Thisforces the heart to beat 15 —that is, the pulse rate increases—and in turn accelerates the riskof a heart attack.
9.
(A) denied
(B) found
(C) created
(D) doubted

參考答案

答案：B
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)

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