发生交叉反应的原因是因为存在（）。 A.同种异型抗原 B.同种抗原 C.异种

阅读理解。

     These strategies(策略) will help you  learn how to take  tests and show what you know. MULTIPLE

-CHOICE(选择题)TEST

     Mark the best answer from a list of choices for a multiple-choice test.

     1．Read  Test  Directions(说明) Carefully.  Directions  tell  what  you  need  to do. Words like best,

always, only, all, and never will help you find the correct answer. Sentences with those words are usually

not true.

     2．Plan Your Time. Pass over hard questions. If you have time, you can go back to them later.

     3．Read Items(题干)Again. If you are not sure about an answer,  read the item again. Think about

all the answer choices. Which one seems best?

     SHORT-ANSWER TEST

     In a short-answer test, write a word, a group of words, or a sentence to answer a question. Look for

key words like who or what that tell you what to write in the answer.

     PASSAGE-WRITING TEST

     For a passage-writing test, write one or more paragraphs to answer one question.

     1．Study the Item and Key Words. Read the question twice or more. Look for key words that tell

you exactly what to do. You might see prompts(提示)like these:

     2．Plan Your Answer. Think about the key words and the topic. Write everything you know about

the topic on a piece of your own paper. This can help you organize(组织)your writing.

     3．Write the Passage. Use the words in the prompts to write a beginning. Then use what you know

about the topic to write your passage.

     Write a topic sentence for each paragraph.

     Write the important information in the body.

     Read your passage before you hand it in.

     You may try these strategies in today's test. We hope you'll have a great success. Good luck!

1．How many kinds of tests are talked about in the passage?

A．One.

B．Two.

C．Three.

D．Four.

2．When you take a short-answer test, you should ________.

A．write words to answer a question

B．circle the best answer from choices

C．write some paragraphs for a question

D．underline right sentences in a passage

3．While you are taking any of the tests, you should think carefully about ________.

A．key words  

B．each paragraph

C．every choice  

D．topic sentences

4．In the passage, the writer mainly wants ________.

A．to show us the differences between the tests

B．to help us to learn how to do well in tests

C．to teach us how to find the key words in the items

D．to introduce the ways to choose the best answers

关于嗜铬细胞瘤患者病理生理改变，错误的是（）。

A.血容量显著减少

B.术中可发生高血压危象

C.肿瘤切除后易发生高血糖

D.多数以分泌去甲肾上腺素为主

E.伴有甲状腺素及肾上腺皮质激素分泌增加

气象信息系统是国家基础信息系统的重要组成部分。要加强国家气象信息共享平台建设，把（）高性能计算机应用中心建设成国内领先、国际先进的计算机系统和网络中心，建设全国统一的气象通信和信息存储、分发系统，充分发挥气象信息网络资源优势，实现观测数据共享。

A.北京

B.上海

C.气象部门

某超市经销甲品牌的电器，产品售价为2000元/台，单位商品变动成本为1500元/台，固定成本分摊为4万元。甲品牌的电器的保本销售量为( )台。

A．80

B．20

C．100

D．27

观察设计和准备不包括的内容是______

A．问题、目的与对象的确定
B．理论准备、内容、项目与表格设计
C．试探性观察与观察取样
D．筹备观察资金