问题 单项选择题

氰化氢引起窒息的机制是

A.麻醉中枢神经,导致神经精神障碍
B.使血氧饱和度下降,组织不能利用氧
C.使血液携氧能力降低,阴止氧合血红蛋白释放
D.引起卟啉代谢障碍,抑制血红素合成
E.与氧化型细胞色素氧化酶中的三价铁结合,抑制酶的活性

答案

参考答案:E

问答题
阅读理解

C.

Here are two letters from our readers expressing their concern about school assessment (评价):

(l)

Students should be allowed to study without worrying about grades (学习成绩). Fortunately, most educators realize that students have different interests and abilities. However, grade-based assessment is still very common. Grades often hold back creativity. Competing for better grades causes many students to turn down opportunities to go in for music, drama and sports. Grades are also an unfair measure of a student’s ability. I do not demand, as some extremists do, that grades should no longer be recorded. However, I do believe that less importance should be placed on. grades. I hope that someday grades will become optional(可选择的) at Village High School.

Magdalena Smith, President

Drama Club

(2)

Let’s face the facts about grades. Grades perform three basic functions( 功能). First, grades get students to work at their highest level of competence  (能力 ). Second, they act as an encouragement for hard-working students and as a warming to those who are not. Finally, grades are an effective standard by which to measure students' achievement. Good grades help students to get jobs and to get into university.

I've spoken with a number of students who have jobs, and most of them say that they were hired mainly because of their grades. My grades helped me get a part-time job and will help me into university next year. I think grades are extremely important at Village High School.

Simon Harper, Member,

Science Club

64. Simon Harper writes from the viewpoint of someone who      

A. insists grades should become optional in the near future

B. believe in the advantages of assessment based on grades

C. is concerned about improving students' creativity

D. supports using students' interests to measure their abilities

65. Magdalena Smith thinks it is important for       .

A. educators to assess the students by grades

B. educators to pay more attention to grades

C. students to compete for better grades

D. students to take part in music, drama, and sports

66. According to the letters, which of the following is TRUE about Village High School?

A. Grades are effective in every way.    

B. Grades hold back students' creativity. .

C. Grades bring about unnecessary worries.

D. Grades are still in use at present.    .

67. What are the two letters mainly about?

A. The role that grades should play in assessing students.

B. The importance of art and music in students' life.

C. The need to have a standard measure for students' success.

D. The reasons why grades shouldn't be used to assess students.