如图所示,倾斜的平行导轨处在匀强磁场中,导轨上、下两边的电阻分别为R1=3Ω和R

题型:选择题

问题:

如图所示,倾斜的平行导轨处在匀强磁场中,导轨上、下两边的电阻分别为R1=3Ω和R2=6Ω,金属棒ab的电阻R3=4Ω,其余电阻不计。则金属棒ab沿着粗糙的导轨加速下滑的过程中

A.安培力对金属棒做功等于金属棒机械能的减少量

B.重力和安培力对金属棒做功之和大于金属棒动能的增量

C.R1和R2发热功率之比P1:P2=1:2

D.R1、R2和R3产生的焦耳热之比Q1:Q2:Q3=2:1:6

考点:电磁感应现象的综合应用
题型:选择题

阅读理解。

    When you are learning a language, listening, speaking and writing are important, but reading can

also be very helpful. When you read, you can not only learn some new words, but also learn how to

use them. When you read a passage, it gives you a good example for writing.

    Here are some good reading tips.

    Firstly, try to read at the right level (水平). Read something that you can understand. If it is too

hard for you, it is not interesting.

    Secondly, try to understand the new words. If there are four or five new words on a page, don't

use a dictionary. Instead, try to guess their meanings as you read. Mark (作标记) them with a pencil.

Then look them up in a dictionary when you finish reading, and write them in your own vocabulary

book. Try to remember them.

    Thirdly, try to read for a short time once a day. Fifteen minutes or half an hour every day is better

than two hours every Sunday. For example, you can read before you go to bed, or after you get up

or at lunchtime.

    Lastly, read something that interests you. Choose a newspaper, a book or a magazine about a

subject that you like. It will be easy enough for you to understand.

1. The underlined word "tips" in the passage means "   '' in Chinese.

A.  末端        

B.  小费        

C.  处所      

D.  建议

2. How many reading tips does the writer give us?

A. Six.          

B. Five.        

C. Four.      

D. Three.

3. If you meet a few new words on a page while reading, you can____. 

A. stop reading

B. guess the meanings at first

C. write them down at once

D. look them up right away

4. Which of the following is TRUE according to the passage?

A. Reading a lot can help you write better.

B. It is useful for you to read for long once a week.

C. When you read, you can only learn some new words.

D. Try to read something hard to make your English better.

5. Which is the BEST title for the passage?

A. How to look up a new word    

B. How to make reading better    

C. How to remember new words

D. How to choose something to read

题型:选择题

指令“ORLA,#80H”的含义是()

A、地址80H中的数和A中数进行“位或”操作,结果在A中

B、立即数80H和A中数进行“位与”操作,结果在A中

C、立即数128和A中数进行“位或”操作,结果在A中

D、立即数80和A中数进行“位或”操作,结果在A中

题型:选择题

比重不同的药物在制备散剂时,采用何种混合方法最佳______。

A.等量递加法
B.多次过筛
C.将轻者加在重者之上
D.将重者加在轻者之上
E.机械法

题型:选择题

甲状旁腺素对血液中钙磷浓度的调节作用表现为

A.降低血钙浓度,升高血磷浓度
B.升高血钙浓度,降低血磷浓度
C.升高血钙浓度,不影响血磷浓度
D.降低血钙浓度,不影响血磷浓度
E.升高血钙、血磷浓度

题型:选择题

零部件损坏的原因是哪些?

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