问题 单项选择题

下面是测定化妆品pH的操作步骤,以下描述中,不对的是()

A.称取定量样品于50ml烧杯,加入9倍重量的水,搅拌并加热至40℃使样品与水充分混合,冷却至室温,测定样品液温度

B.按仪器要求准备pH计,并将温度补偿器调至样品液的温度

C.预计样品的pH呈碱性,分别从标准磷酸缓冲液和硼酸缓冲液的试剂瓶中倒出约10ml溶液于小烧杯中反复校正pH计

D.边搅拌边测定样品的pH,当读数稳定后,记录读数

E.全部测定完毕后,按仪器要求,冲洗电极,并将甘汞电极的橡皮塞/帽套上,玻璃电极浸泡在纯水中,缓冲液倒回瓶中

答案

参考答案:E

单项选择题
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     Everyone knows about straight-A students. We see them frequently in TV situation comedies and in

movies like Revenge(复仇) of the Nerds. They get high grades, all right, but only by becoming dull

laborers, their noses always stuck in a book. They are not good at social communication and look

clumsy when it comes to sports.  

     How, then, do we account for Domenica Roman or Paul Melendres?  

     Roman is on the tennis team at Fairmont Senior High School. She also sings in the choral group,

serves on the student council(学生会) and is a member of the mathematics society. For two years she

has maintained A's in every subject. Melendres, now a freshman at the University of New Mexico, was

student-body president at Valley High School in Albuquerque. He played soccer and basketball well,

exhibited at the science fair, and meanwhile worked as a reporter on a local television station. Being a

speech giver at the graduation ceremony, he achieved straight A's in his regular classes, plus bonus points

for A's in two college-level courses.  

      How do super-achievers like Roman and Melendres do it? Brains aren't the only answer. "Top

grades don't always go to the brightest students," declares Herbert Walberg, professor of education at

the University of Illinois at Chicago, who has conducted major studies of super-achieving students.

"Knowing how to make the most of your innate(天赋的) abilities counts for more. Much more."  

     In fact, Walberg says, students with high I.Q.s sometimes don't do as well as classmates with lower I.Q.s. For them, learning comes too easily and they never find out how to get down.   Hard work isn't the

whole story, either. "It's not how long you sit there with the books open," said one of the many A students we interviewed. "It's what you do while you're sitting." Indeed, some of these students actually put in

fewer hours of homework time than their lower-scoring classmates.  

     The kids at the top of the class get there by mastering a few basic techniques that others can readily

learn.

1. The "nerds" can probably be __________.

A. dull bookworms lacking sports and social skills

B. successful top students popular with their peers

C. students with certain learning difficulties

D. born leaders crazy about social activities

2. What can we conclude from the first paragraph?

A. Most TV programs and films are about straight-A students.

B. People have unfavorable impression of straight-A students.

C. Everyone knows about straight-A students from TV or films.

D. Straight-A students are well admired by people in the society.

3. Some students become super-achievers mainly because ________.

A. they are born cleverer than others

B. they worker longer hours on study

C. they make full use of their abilities

D. they know the short cut to success

4. What will be talked about after the last paragraph?

A. The interviews with more students.

B. The role I.Q. plays in learning well.

C. The techniques to be better learners.

D. The achievements top students make.

5. What can we infer from the passage?

A. Students needn't work hard on study any more.

B. The brightest students can never get top grades.

C. Top students certainly achieve all-around developments.

D. Students with average I.Q.s can become super-achievers.