问题 单项选择题 单选题

机械安全的安全性指的是()。

A.机器在预定的使用条件下,在其寿命期限内必须按照使用说明正确使用才是安全的

B.机器在预定的使用条件下,在其寿命期限内即使发生误操作,也能保证人和机器的安全

C.机器在预定的使用条件下,在其寿命期限内无论如何操作都是安全的

D.机器在预定的使用条件下,在其寿命期限内无论如何操作都不是绝对安全的,只是安全达到了可接受的程度

答案

参考答案:B

综合
阅读理解

阅读理解

     In a new study about the way kids learn math in elementary school, Beilock and Levine found a

surprising relationship between what female teachers think and what female students learn: If a female

teacher is uncomfortable with her own math skills, then her female students are more likely to believe

that boys are better than girls at math.

     " If these girls keep getting math-anxious female teachers in later grades, it may create a snowball

effect on their math achievement," Levine told Science News. In other words, girls may end up learning

math anxiety from their teachers. The study suggests that if these girls grow up believing that boys are

better at math than girls are, then these girls may not do as well as they would have if they were more

confident.

      The researchers also gave the students tests to tell whether the students believed that a math

superstar had to be a boy. Then the researchers turned to the teachers: To find out which teachers

were anxious about math, the researchers asked the teachers how they felt at times when they came

across math, such as when reading a sales receipt. A teacher who got nervous looking at the numbers

on a sales receipt, for example, was probably anxious about math.

     Boys, on average, were unaffected by a teacher's anxiety. On average, girls with math-anxious

teachers scored lower on the end-of-the-year math tests than other girls in the study did. Plus, on the

test showing whether someone thought a math superstar had to be a boy, 20 girls showed feeling that

boys would be better at math - and all of these girls had been taught by female teachers who had math

anxiety.

     According to surveys done before this one, college students who want to become elementary

school teachers have the highest levels of anxiety about math. Plus, nine of every 10 elementary teachers

are women, Levine said.

1. Which of the followings is NOT the study mentioned in the passage?

A. Girls may be bad at math because of their female teachers' anxiety.

B. Most students tend to believe that a math superstar has to be a boy.

C. What kind of teachers is more likely to have math anxiety.

D. On average boys are also affected by a teacher's anxiety.

2. What can you infer from the second paragraph?

A. Girls can do as well as boys if they are confident.

B. Girls are born much weaker than many boys.

C. Boys are stronger and better in math than girls.

D. Girls who are bad at math can do other things better.

3. According to the last paragraph, Levine's imply attitude to the math teaching in elementary schools

    is _______.

A. hopeful

B. disappointed

C. worried

D. content