关于ERG的b波起源正确的是（）。 A.视网膜色素上皮 B.光感受器 C.视网膜神经

阅读理解。

     For some people, it's easy to get dressed for work. Pilots and police officers, for example, don't have

to make decisions about their work clothes. They wear uniforms to work every day.

     For many office workers, however, it is more difficult to choose clothes for work. They do not wear

uniforms to the office. Also, many organizations are changing their dress codes. They are allowing their

employees (员工) to wear casual clothes to work. 

    The change to casual (随意的) work clothes began in the 1990s. At first, many companies (公司) in

the United States allowed employees to wear casual clothes on one day of the week - Friday. Friday became

"Casual Friday" or "Dress-down Friday". Today, however, many companies are allowing their employees

to wear casual clothes every day of the week.

     Why are companies allowing their employees to wear casual clothes? Some studies show that people

are producing and achieving more when they are wearing comfortable clothes. Some companies also like

the casual dress code because they don't need to buy special clothes for work. They can save money this

way.

     Unfortunately, a casual dress code can also cause problems. Sometimes employees dress too casually.

They think they can wear anything. Many companies have rules (要求) about casual clothes. They list the

kinds of clothes that are not "business-casual" clothes. Blue jeans, sandals, and sportswear are examples

of clothes that are usually too casual for the office.

1. What do pilots and police officers wear to work? [ ]

A. Casual clothes.

B. Sportswear.

C. Blue jeans.

D. Uniforms.

2. What does "a dress code" mean? [ ]

A. It tells what you can do and can't do.

B. It is a rule about what clothes to wear.

C. It saves a lot of money.

D. It shows you what to say at work.

3. "Dress-down Friday" is a day when employees are allowed to           . [ ]

A. eat delicious food

D. have smart uniforms on

C. wear casual clothes to work

D. work longer hours

4. Why do some companies agree to the casual dress code? [ ]

A. They don't need to buy special clothes for work.

B. It is difficult for them to choose clothes for work.

C. They don't like the same uniform.

D. It is easy for them to make decisions about work clothes.

5. What problems can a casual dress code cause according to the passage? [ ]

A. Employees seldom wear comfortable clothes.

B. Usually employees put on expensive clothing.

C. Employees always have too little on themselves.

D. Sometimes employees dress too casually.

酸类物质是白酒中的协调成分，功能相当丰富，阐述其对白酒的主要贡献。

铬黑T指示剂属于哪种指示剂（）

A.酸碱指示剂

B.金属指示剂

C.氧化还原指示剂

D.沉淀滴定指示剂

湿式空气滤清器中必须加机油。

水溶性的小分子物质和水可通过何种方式通过生物膜（）

A.溶解扩散

B.限制扩散（微孔途径）

C.主动转运

D.易化扩散

E.胞饮作用