问题 阅读理解

阅读理解。

     One of the most difficult problems a young person faces is deciding what to do. Some people,

however, from the time they are six years old "know" that they want to be doctors or teachers or

firefighters, but most of us do not get around to making a decision about a job until someone or

something forces us to face the problem.

     Choosing a job takes time, and there are a lot of things you have to think about as you try to

decide what you would like to do. You may find that you will have to take special courses for a

particular kind of work, or you may find out that you will need to get enough knowledge for a

particular job.

     Fortunately, there are a lot of people you can turn to for advice and help in making your decision.

At most schools, there are teachers to give you information about jobs. And you can talk over your

ideas with family members and friends who are always ready to listen and to offer suggestions.

1. In the third paragraph "turn to" means ______.

A. turn your face around    

B. change into  

C. go to someone for help  

D. give advice

2. The best title of this passage is ______.

A. Getting a Job

B. Kind People to Help You

C. Choosing a job

D. Difficulties Facing Young People

3. The passage tells you that ______ for a particular job.

A. you should have ideas when you are a child

B. it's impossible for you to get enough knowledge

C. you have to face the problem

D. you may enter a class to study

4. Making a decision about choosing your job ______.

A. needs friends

B. needs time  

C. cost money

D. cost your ability

答案

1-4: CCCB  

实验题

(10分)从今年3月16日下午开始,大陆“海水受日本核辐射污染,碘可防辐射”等消息疯传,从绍兴、宁波、台州地区开始出现抢盐潮,接着蔓延到多个城市,人们抢购加碘盐是因为食盐中添加了碘元素。

I.人们在即将受到核辐射前的24小时内,需在医生指导下服用碘片,成人推荐服用量为100mg碘,假设此碘盐碘元素含量为40 mg/kg,要达到上述碘含量要求,需服用该碘盐        kg,你觉得服用碘盐防辐射合理吗?        

II.如图为某加碘盐标签的一部分。

已知:①KIO3+5KI+3H2SO4=3K2SO4+3I2+3H2O②I2+2Na2S2O3=2NaI+Na2S4O6(无色)

某同学欲测定此加碘盐中碘元素的含量,进行以下实验:

步骤1:称取ag市售食盐,配成溶液,全部转移

至锥形瓶中,加入适量新制KI溶液,滴入几滴稀硫酸,溶液变黄色,再加入3滴淀粉溶液。

步骤2:取一支50mL碱式滴定管,用bmol·L-1的新制Na2S2O3 溶液润洗2~3次后,装满溶液,调节液面高度至0刻度。

步骤3:开始滴定直至终点,重复操作2~3次,实验数据记录如下:

编号碱式滴定管读数消耗体积(mL)
滴定前刻度滴定后刻度
10如图一 
2023.9823.98
3024.0224.02
(1)第一次读数为        mL。

(2)滴定终点的判断方法        

(3)经过计算,此加碘盐碘元素的含量为        mg/kg(用包含a、b的最简表达式表示)。

(4)下列操作可能会导致测量结果偏低的是        

A.步骤1中称取食盐时将砝码放在左盘,食盐放在放在右盘,游码读数为0.5g

B.步骤1所配食盐溶液未完全转移至锥形瓶

C.步骤2中滴定管洗涤后未润洗

D.步骤3滴定前滴定管尖嘴处有气泡,滴定后气泡消失

单项选择题