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问题 单项选择题

以下关于淋巴细胞功能测定体外实验说法错误的是（）

A.包括淋巴细胞增殖反应

B.包括淋巴细胞介导的细胞毒试验

C.用于淋巴细胞分泌功能的测定

D.进行迟发型超敏反应

E.常用可传代的已建株的人肿瘤细胞进行细胞毒试验

答案

参考答案：D

解析：淋巴细胞功能测定可分为体内试验和体外实验。体内试验主要是进行迟发型超敏反应，借此间接了解淋巴细胞对抗原、半抗原或有丝分裂原的应答反应；体外试验主要包括淋巴细胞对抗原或有丝分裂原刺激后的增殖反应、细胞毒性试验及淋巴细胞分泌产物的测定。

多选题
从同一地点同时开始沿同一直线运动的两个物体I、II的速度图象如图所示．在0～t2时间内，下列说法中正确的是（   ）

A．I物体所受的合外力不断减小，II物体所受的合外力一定不变

B．t2时刻两物体相遇

C．在第一次相遇之前，t1时刻两物体相距最远

D．I、II两个物体的平均速度大小都是
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单项选择题 案例分析题

The food we eat seems to have profound effects on our health.Although science has made enormous steps in making food more fit to eat ,it has, at the same time,made many foods unfit to eat. Some research has shown that perhaps eighty percent of all human illnesses are related to diet and forty percent of cancer is related to the diet as well,especially cancer of the colon. Different cultures are more likely to cause certain different illnesses because of the food that is characteristic in these cultures. That food is related to illness is nto a new discovery. In 1945, about 35 years ago, government researchers realized that nitrates, commonly used to preserve color in meats,and other food additives,caused cancer. Yet, these carcinogenic additives remain in our food, and it becomes more difficult all the time to know which things on the packaging labels of processed food are helpful or harmful. The additives which we eat are not all so direct. Farmers often give penicillin to beef and living animals, and because of this ,penicillin has been found in the milk of treated cow. Sometimes similar drugs are given to animals not for medical purposes,but for financial reasons. The farmers are simply trying to fatten the animals in order to obtain a higher price on the market. Although the Food and Drug Administration(FDA) has tried repeatedly to control these procedures, the practices continue.

What are nitrates used for?（）

A.They preserve flavor in packaged foods.

B.They preserve the color of meats.

C.They are the objects of research.

D.They cause the animals to become fatter.
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