统计过程控制的主要工具是（）。A、过程能力指数 B、概率统计 C、坐标图 D、控制图

现有一批产品，其使用寿命服从参数为λ的指数分布，平均寿命(EX)为400(小时)．今从中随意取出200个产品，分装成100盒，每盒2个．如果盒中2个产品使用寿命都超过500(小时)，那么这盒产品被定为优质品，记

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1.求Y_i的分布；

     What do you want to be in the future? One way to answer this question is to make a career plan. A

career plan shows the steps you need to take to reach your career goal.

Steps to making a career plan:

     1. Thinking about your skills and interests can help you find a satisfying career. Determine your

interests, think about what you'd like to do. Think about experiences you have enjoyed. Make a list of

activities you have enjoyed during the past few years. Then make a list of skills you have. Even if you

haven't been employed before, you should have some skills which will help you find a job. For example,

if you volunteered at a hospital and enjoyed the experience, you may want to consider a medical career.

     2. Find out the types of careers that are suitable to you. If you don't research careers, you may not

know about the best jobs to fit your interests and skills.  It's also important to decide if the career you are

considering is really what you expect and whether it offers the salary and benefits you want. One good

way to learn about a career is to talk to someone who is in the career now.

     3. Once you have determined what career path you want to follow, think about what you need to do

to prepare for that career. Do you need special training? What kind of experience will you need to be

successful in the career?

1. What would be the best title for the passage?  

A. What job would you like to do?      

B. How to make a career plan?  

C. Which job is a good one?          

D. Prepare for your future.  

2. According to the passage, to find a satisfying job in the future, you need to _____.

A. talk with the employers    

B. think about your interests and skills

C. write many applications    

D. volunteer to work at a hospital 

3. According to the passage, which job is suitable to you? 

A. A job that fits your interests and skills.  

B. A job that your parents are doing.

C. A job that needs special training.

D. A job that your parents expect you to get. 

4. Where is the passage probably taken from?

A. An ad in a newspaper.      

B. A travel guidebook.  

C. A science book.            

D. A Web site about careers.

关于神经鞘膜瘤说法正确的是（）。

A.多为孤立性肿块

B.很少恶变

C.部分肿块可以向咽侧壁突出

D.无明显包膜

E.肿块较大时可压迫神经

( )比桌面演练规模大，因而协调工作的难度也随着更多组织的参与而加大。

A．全面演练

B．部分演练

C．个别演练

D．功能演练

育种工作者利用不同的方法进行了如下四组实验。请据图回答问题。

已知番茄的红果（Y）对黄果（y）为显性，少室（M）对多室（m）为显性，控制两对相对性状的基因分别位于两对同源染色体上。用红果多室（Yymm）番茄植株的花粉进行Ⅱ、Ⅲ有关实验，则II过程中，从花粉形成幼苗B所进行的细胞分裂方式是（）。Ⅲ过程中植物体C的基因型有（）。