什么叫初至切除？

关于IUD.的不良反应，错误的是（）。

A.出血常发生于放置IUD.后1年内，尤其是最初3个月

B.上环后腰酸腹坠是因为IUD.刺激引起子宫收缩所致

C.出血的原因是因为IUD.刺激纤溶系统活性增加所致

D.术时选择与子宫腔大小、形态相符的IUD.，可杜绝副反应的发生

E.上环后出血经治疗3个周期仍未见效者应考虑取环

癌痛的三阶梯用药原则以下哪项不正确()

A．阶梯给药

B．口服给药

C．按需给药

D．用药个体化

E．辅助用药

阅读理解

     Going to school means learning new skills and facts in such subjects as reading, math, science, history, art or music. Teachers teach and students learn, and many scientists are interested in finding ways to

improve both the teaching and learning processes.

     Some researchers, such as Sian Beilock and Susan Levine, are trying to learn about learning. Beilock

and Levine are psychologists at the University of Chicago. Psychologists study the ways people think and behave, and these researchers want to know how a person's thoughts and behavior are related.

     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. 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.

     Just as students find certain subjects to be difficult, teachers can find certain subjects to be difficult to

learn-and teach. The subject of math can be particularly difficult for everyone. Researchers use the word

"anxiety" to describe such feelings: anxiety is uneasiness or worry. (Many people, for example, have

anxiety about going to the dentist because they're worried about pain.)

     The new study found that when a teacher has anxiety about math, that feeling can influence how her

female students feel about math. The study involved 65 girls, 52 boys and 17 first- and second-grade

teachers in elementary schools in the Midwest. The students took math achievement tests at the beginning

and end of the school year, and the researchers compared the scores.

     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.

     This study was small, and it's often difficult to see large patterns in small studies, David Geary told

Science News. Geary, a psychologist at the University of Missouri in Columbia, studies how children

learn math. "This is an interesting study, but the results need to be interpreted as preliminary and in need

of replication with a larger sample," Geary said. That means that the results are just showing something

that might be happening, but more studies should be done. If more studies find the same trend as this one,

then it's possible that a teacher's anxiety over math really is affecting her female students.

1. Sian Beilock and Susan Levine carried out the new research in order to ______.

A. know the effects of teaching on learning      

B. study students' ways of learning math

C. prove women teachers are unfit to teach math  

D. find better teaching methods for teachers

2. The underlined part in paragraph 4 most probably means that girls may ______. 

A. end up learning math with anxiety from their teachers

B. study the ways their female teachers behave

C. have an influence on their math-anxious female teachers

D. gain unexpected achievement in such subjects as math

3. In the study, what were the teachers required to do?  

A. Prepare two math achievement tests for the students.

B. Tell their feelings about math problems.

C. Answer whether a math superstar had to be a boy.

D. Compare the students' scores after the math tests.

4. What is the finding of the new study?  

A. No male students were affected by their teachers' anxiety.

B. Almost all the girls got lower scores in the tests than the boys.

C. About 30% of the girls thought boys are better at math than girls.

D. Girls with math-anxious teachers all failed in the math tests.

5. Which of the following is TRUE according to the text?

A. 117 students and teachers took part in the new study.

B. The researchers felt surprised at the findings of their study.

C. Beilock and Levine are interested in teaching math.

D. Men teachers are better at teaching math than women teachers.

当井上有H₂S时，施工作业前应主要携带哪些应急物资？

决定钎料钎缝强度的主要因素是（）。

A.钎料成分

B.钎剂

C.助焊剂