以下哪种属于多发伤()。 A.同一致伤物只损伤了角膜 B.同一致伤物即损伤了角膜,也

题型:单项选择题 A1型题

问题:

以下哪种属于多发伤()。

A.同一致伤物只损伤了角膜

B.同一致伤物即损伤了角膜,也损伤了晶状体玻璃体

C.同一致伤物即损伤了眼睑,也损伤了角膜、晶状体

D.2种以上致伤因素同时作用于眼部造成损伤

E.2种以上致伤因素先后作用于眼部造成损伤

考点:眼科主治医师眼科专业知识主治医师(眼科)专业知识模拟试题四
题型:单项选择题 A1型题

A series of stimulus policies and supportive measures taken by the government ________ to promote change in the economic environment in this area.

A.are expecting

B.are expected

C.is expecting

D.is expected

题型:单项选择题 A1型题

采用安全特低电压是( )的措施。

A.只用于直接接触电击保护

B.只用于间接接触电击保护

C.用于防止爆炸火灾危险

D.用于直接接触电击保护和间接接触电击保护

题型:单项选择题 A1型题

In a society such as the United States or Canada,which has many national, religious,and cultural differences, people highly value individualism(个人主义)— the differences among people, Teachers place a lot of importance on the qualities that make each student special.The educational systems in these countries show these values.Students do not memorize information.Instead, they work individually and find answers themselves.There is often discussion in the classroom.At an early age, students learn to form their own ideas and opinions.

In most Asian societies, on the contrary, people have the same language, history, and culture. Perhaps for this reason, the educational system in much of the Orient (东方) reflects society’s belief in group goals and purposes rather than individualism.Children in China, Japan, and Korea often work together and help one another on assignments. In the classroom, the teaching methods are often very formal.The teacher lectures, and the students listen.There is not much discussion. Instead, the students repeat rules or information that they have memorized.

There are advantages and disadvantages to both of these systems of education. For example, one advantage to the system in Japan is that students there learn much more math and science than American students learn by the end of high school. They also study more hours each day and more days each year than North Americans do. The system is difficult, but it prepares students for a society that values discipline and self-control.There is, however, a disadvantage. Memorization is an important learning method in Japanese schools, yet many students say that after an exam, they forget much of the information they have memorized.

The advantage of the educational system in North America, on the other hand, is that students learn to think for themselves. The system prepares them for a society that values creative ideas.There is, however, a disadvantage.When students graduate from high school,they haven’ t memorized as many basic rules and facts as students in other countries have.

1、The reason why American teachers attach much importance to individualism is that ______________.

A.they are required to do so

B.their students do not memorize information

C.the United States is a country of many cultures

D.their students work individually

2、Which of the following statements applies to Asian methods of education? 

A.Each child in a classroom draws a different picture

B.Students have to find information themselves.

C.Students are prepared for a society that values discipline

D.Teachers serve as a guide in discussion

3、A good educational system would be the one that  ______________.

A.has more advantages

B.is the combination of Western and Oriental methods

C.is based on the Western system

D.rests on the Asian system

4、The author believes that ______________.

A.different educational systems reflect different culture of the societies

B.students from Western countries are creative but selfish

C.Asian students are merely interested in math and science

D.there are more advantages to Western system of education than to Oriental one

5.The author focuses on ______________.

A.the differences in methods of education orient and west

B.the advantages and disadvantages to both of the Western and Asian educational system

C.how Asian school systems reflect group goals

D.how Western school systems reflect the value of individualism

题型:单项选择题 A1型题

(16分)聚乙烯醇是生产合成纤维——维纶、黏合剂——胶水、涂料、婴儿尿不湿布料的一种重要化工原料。聚乙烯醇因具有水溶性,不释放有机溶剂污染环境而备受人们的喜爱。下面是生产聚乙烯醇的一种反应原理。

羧酸酯RCOOR′在催化剂存在时可跟R″OH醇发生如下反应(R′,R″是两种不同的烃基):RCOOR′+R″OHRCOOR″+R′OH,此反应称为酯交换反应,常用于有机合成中,在合成维纶的过程中,有一个步骤是把聚乙酸乙烯酯转化成聚乙烯醇,这一步就是用过量的甲醇进行酯交换反应来实现的。

请完成下列问题:

(1)反应中甲醇为什么要过量?__________________________________________________。

(2)写出聚乙烯醇的结构简式:____________________________________________________。

(3)写出聚乙酸乙烯酯与甲醇进行酯交换反应的化学方程式:__________________________。

与水解反应类似,在一定条件下,酯也能发生氨解反应。请写出下列反应方程式,并指出反应类型。

(4)聚乙酸乙烯酯的水解:_________________,______________________________________。

(5)聚乙酸乙烯酯的氨解:_________________,______________________________________。

题型:单项选择题 A1型题

在油包水乳化钻井液中,油是分散相。

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