问题 单项选择题

维生素B1().

A.遇酸容易脱水生成脱水产物 

B.与空气长期接触遇光氧化生成硫色素 

C.体内代谢磷酸化后生成黄素单核苷酸 

D.有吡多醇(吡多辛)、吡多醛、吡多胺三种形式 

E.容易被氧化生成多聚糠醛,这也是其变色的主要原因

答案

参考答案:B

单项选择题
阅读理解

                                         Rules for the University Entrance Examination

     1     If you are more than ten minutes late, you may not enter the examination center. The examination

takes place at the same time in different states.

You must have proof of your name and grade as well as official examination number. Show these when

you come to the examination center.

     2      Mathematics examinations may allow you to use electronic calculators. Other subjects may allow

you to use dictionaries and other reference material. Please read the notes sent with your timetable

carefully. You must bring your own pencils. None will be provided for you. The following items are not

allowed in the examination center: walkmans and radios, head sets, any food or drink, school bags,

electronic equipment (unless specifically permitted for various subjects), and mobile phones.

You must remain silent during the examination.      3       

If you need a drink or toilet break, you should raise your hand and wait for the supervisor to speak to you.

     4       You are not allowed to talk with anyone during the break.

The supervisor will warn you fifteen minutes, five minutes and one minute before the end of the

examination.        5        

A. Depending on which examination you are taking, you may bring certain items into the examination

center.

B. You will be given water or the supervisor will take you to the bathroom.

C. You must be at the examination center ten minutes before the examination starts.

D. When the supervisor says that the time is up, you must put down your pencil and wait at your desk until your paper is collected.

E. You may leave the examination room at any time if you do not plan to return.

F. You must not disturb other people who are taking the test.