问题 单项选择题

SABC法的基本原理是()

A.链霉亲和素同一定浓度的生物素化酶混合后,形成链霉亲和素一生物素酶复合物,此复合物可以和各种生物素标记抗体结合

B.链霉亲和素同一定浓度的卵白素化酶混合后,形成链霉亲和素一卵白素一酶复合物,此复合物可以和各种卵白素标记抗体结合

C.亲和素同一定浓度的生物素化酶混合后,形成亲和素一生物素一酶复合物,此复合物可以和各种生物素标记抗体结合

D.亲和素同一定浓度的卵白素化酶混合后,形成亲和素一卵白素一酶复合物,此复合物可以和各种卵白素标记抗体结合

E.链霉亲和素同一定浓度的辣根过氧化物酶混合后,形成链霉亲和素一酶复合物,此复合物可以和各种生物素标记抗体结合

答案

参考答案:A

阅读理解

阅读理解。

     The horsepower was first used two hundred years ago. James Watt had made the world's first widely

used steam engine. He had no way of telling people exactly how powerful it was, for at that time there were

no units for measuring power.

     Watt decided to find out how much work one strong horse could do in one minute. He called that init one

horsepower. With this unit he could measure the work his steam engine could do.

     He discovered that a horse could lift a 3,300-pound weight 10 feet into the air in one minute. His engine

could lift a 3,300 pound weight 100 feet in one minute.

     Because his engine did ten times as much work as the horse, Watt called it a ten-horsepower engine.

1. Watt made the world's first _____.

A. train

B. engine

C. steam engine

D. bus

2. Watt wanted to find a way _____.

A. to lift a 3,300-pound weight

B. to show how useful his steam engine was

C. to tell people exactly how powerful his steam engine was

D. to measure the weight of his steam engine

3. What does one horsepower mean? It means _____.

A. one horse's power

B. what one strong horse can do in one minute

C. what one horse can do in a day

D. what work one horse can do as much as possible

4. Which is not true? 

A. Watt decided to find out how much work one strong horse could do in one minute.

B. Watt decided to make the world's first widely used horse engine.

C. He wanted to find a way to tell people exactly how powerful his engine was.

D. He wanted to measure the work his engine could do.

5. The best headline for the article is _____.

A. Horsepower

B. Watt's steam engine

C. A ten-horsepower engine

D. The beginning of horsepower

单项选择题