问题 单项选择题

抗原抗体形成明显沉淀物的条件是()

A.抗体多于抗原

B.抗原多于抗体

C.抗原抗体一样多

D.抗原抗体比例合适

E.不必考虑抗原抗体的比例

答案

参考答案:D

解析:抗原和抗体的比例是沉淀形成的关键因素,抗原和抗体比例恰当时,二者充分结合,形成沉淀最多。

阅读理解

阅读理解。

     In the mid-1940s, the young ambitious Ruth and Elliot Handler, owned a company that made wooden

picture frames. In 1945, Ruth and Elliot joined their close friend Harold Mattson to form a company that

would be known for the most famous and successful doll ever created. This company would be named

Mattel after Mattson and Elliot.

      In the mid-1950's, while visiting Switzerland, Ruth Handler purchased a German Lilli doll. Lilli was a

shapely, pretty fashion doll first made in 1955. She was originally fashioned after a famous cartoon character

in the West German Newsletter, Build.

     Lilli is the doll that would inspire Ruth Handler to design the Barbie doll (芭比娃娃). With the help of her

technicians and engineers at Mattel, Barbie was born. Ruth then hired Charlotte Johnson, a fashion designer,

to create Barbie's wardrobe. It was in 1958 that the patent for Barbie was obtained. This would be a fashion

doll unlike any of her time. She would be long-limbed (长肢的), shapely, beautiful, and only 11.5 inches tall.

Ruth and Elliot would name their new fashion doll after their own daughter, Barbie.

     In 1959, the Barbie doll would make her way to the New York Toy Show and receive a cool reception

from the toy buyers.

     Barbie has undergone a lot of changes over the years and has managed to keep up with current trends in

hairstyles, makeup and clothing. She is a reflection of the history of fashion since her introduction to the toy

market.

     Barbie has a universal appeal and collectors both young and old enjoy time spent and memories made with

their dolls.

1. What can we know about Barbie from the passage?

A. She was fashioned after a famous cartoon character.

B. She reflects the history of fashion.

C. She was first made in 1958.

D. She was Ruth's daughter's doll.

2. When Ruth and Elliot created the first doll, _____.

A. they had learned about the toy market

B. they asked a fashion designer to help

C. the doll had a universal appeal

D. the doll had created a promising market

3. The Barbie doll is well received because _____.

A. she is always keeping up with fashion

B. she stands for the toy tendency

C. she is popular with children

D. she has a large market in the world

4. Which is the best title for this passage?

A. Barbie Doll-Symbol of Fashion

B. Barbie Doll-Toy of New Time

C. Current Trend of Barbie Doll

D. Birth and Popularity of Barbie Doll

单项选择题