单选题 Hypertension is the medical term for persistent and sustained high blood pressure. It is one of the most (51) forms of heart disease. An understanding of blood pressure in (52) , healthy individuals is necessary in order to understand hypertension.
Blood pressure is simply the force (53) against the walls of the body's arteries (血管) as blood flows through. The force, produced primarily by the pumping (54) of the heart, is essential for the (55) of the blood and its life-supporting nutrients(营养) to all parts of the body. Every time the heart (56) , called a systole, blood pressure increases. When the heart relaxes (57) beats(diastole), the pressure decreases. The normal systolic pressure of a person at vest is between 100 to 140, and the normal diastole is 60 to 90. Blood-pressure readings are expressed by both (58) , with the systolic over the diastolic: for example, 140/90.
As these ranges suggest, there is a wide (59) of blood pressure for healthy people. Also, blood pressure (60) for healthy people during different times of the day and under different. (61) . It is lower when an individual is asleep than when he is excited or exerting himself physically. Therefore, a single blood-pressure reading above 140/90 does not (62) abnormality. When the pressure is continuously (63) , a person is considered to be suffering from hypertension.
Hypertension is a stealthy(隐秘的) problem: a physician can discover it easily enough, but not a patient. (64) elevations, for example, may produce headaches, dizziness, fatigue, and weakness. But the patient is not likely to (65) these symptoms as having any other source than the increased elevation.

单选题 A. general B. common C. extensive D. usual

单选题 A. average B. normal C. regular D. steady

【正确答案】 B

【答案解析】[解析] normal指人时意为“智力正常的、精神健全的”，合句意。average 意为“平常的、普通的”，与ordinary含义相近。两词相比，average与healthy的含义没有normal与healthy的含义更为接近。另外，average与healthy不是同一丢面上的修饰词，句中逗号起的是一个连词and的作用，故average不能成为答案。如果去掉healthy前面的逗号，那么，答案就可是average了。regular修饰人时意为“(person who)going somewhere and doing something often”，例如：He was one of the regular visitors at the pub where I worked last year. stready也可修饰人，但意为“稳定的、不变的、踏实”。例如：He is a steady young man.

单选题 A. exerted B. exercised C. stimulated D. aroused

【正确答案】 A

【答案解析】[解析] exert可与force，influence，pressure，authority等词一趋使用，意为“施加”；exercise与authority，a right，a responsibility连用，意为“行使”；stimulate意为“刺激/激发”；arouse常与interest，expectations，anger，fear，dislike等词连用，意为“唤起、唤醒、引起”。本句含义为“血压只是流过血管时向人体血管壁施加的力”。A合句意。