90. I think this is a good chance for you to... 我认为这是你…;-的一个好机会. I think this is a good chance for you to test your English. 我认为这是测试你英语的一个好机会. 91. I think it is a good idea to... 我认为……是个好主意. I think it is a good idea to do exercise every day. 我认为每天做运动是个好主意. 92. I think it is a waste of money / time doing... 我觉得……是浪费树时间. I think it is a waste of time sitting in front of the television all day. 我觉得整天看电视是浪费时间. 93 .I think it's wrong to...我认为……是不对的. I think it's wrong to impose your thoughts on others. 我认为把自己的想法强加给别人是不对的. [impose v. 强加;利用] 94. I think that it is impossible to... 我觉得……是不可能的. I think that it is impossible to be there before eight. 我觉得在8点之前赶到那里是不可能的. 95. I think you might like to...我想你可能会喜,灯想……. I think you might like to know something about the new album. 我想你可能会想知道一些关于这张新专辑的介绍. 96. I think you'd better... 我觉得你最好……. I think you'd better hurry up, or you will be late. 我觉得你最好快点,要不就迟到了. 97. I want to express my gratitude to... 我要感谢……. I want to express my gratitude to my family for their support. 我要感谢我的家人给我的支持. 98. I was impressed by... 我被……打动了./……给我留下深刻印象. I was impressed by his inspiring words, and I decided to cooperate with him. 他令人鼓舞的话打动了我,我决定跟他合作. 99. 1 wonder / was wondering if... 我想知道…….我在想是否……. 1) I wonder if I could take this dictionary home. 我想知道我能否把这本字典带回家. 2) I was wondering if you'd like to go to a concert tomorrow night. 我在想你明天晚上是否愿意去听演唱会. 100. I demanded (that)...我要求……. [宾语从句虚拟语气] I demanded (that) I see the principal right away. 我要求马上见校长.

51. I am very pleased to have this opportunity to... 我很高兴有机会……. I am very pleased to have this opportunity to stand here and give you a speech. 我很高兴有机会站在这里为你们演讲. 52. I apologize for... 我为……道歉. I apologize for leaving you alone. 很抱歉把你一个人留下. 53. I believe (that)... …我相信……. I believe that we can conquer cancer totally some day. 我相信我们总有一天能够完全战胜癌症. 54. I believe we should... 我认为我们应该……. I believe we should work together to protect our environment. 我认为我们应该携手保护环境. 55. I can't imagine... 我无法想像……. I can't imagine what my life would be like if I were disabled. 我无法想像如果我身患残疾,我的生活会怎样. 56. I can't stand it when... 我无法忍受……. I can't stand it when people talk with their mouth full. 我无法忍受别人说话的时候满嘴食物. 57.I didn't expect to...我没想到……. I didn't expect to receive such a pretty card from him. 我没想到能收到他寄来的那么漂亮的卡片. 58. I didn't mean to... 我不是有意……. I didn't mean to offend you. 我不是有意要冒犯你的. [offend n.冒犯;得罪] 59. I didn't realize... 我不知道…….俄没意识到……. I didn't realize how much this meant to you. 我没意识到这对你意义有多大. 60. I (don't) feel like... 我(不)想……. 1) I feel like going rock climbing with you this weekend. 这周末我想和你一起去攀岩. 2) I really don't feel like going to the movies tonight. 我今晚真的不想去看电影. 61 . I don't get very excited about... 我对……不怎么感兴趣. I don't get very excited about going to the concert. 我对去听演唱会不怎么感兴趣. 62. I don't know how to... 我不知道如何……. I don't know how to answer the question. 我不知道如何回答这个问题. 63. I don't see (that)... 我看不出…….我认为……不……. I don't see (that) she really intends to help us out. 我觉得她并不打算帮助我们. 64. I don't think it is necessary to... 我认为没有必要……. I don't think it is necessary to leave so early.我认为没有必要这么早走. 65. I don't think it's right to... 我认为……是不对的. I don't think it's right to bad mouth other people. 我认为说别人坏话是不对的. 66. I doubt that /if /whether... 我怀疑哦不相信……. I doubt if what he said is true. 我不相信他所说的是真的. 67.I dream of... 我梦想……. I dream of being a successful salesman. 我梦想成为一名成功的推销员. 68. I'm dying to... 我渴望…….俄盼望……. I'm dying to leave for Beijing to meet my parents. 我盼望着去北京见我的父母. 69. I feel very honored to... 我觉得很荣幸……. I feel very honored to be a member of this team. 能成为这个队的一员我深感荣幸. 70. I'm fed up with... 我厌倦了…….我受够了……. I'm fed up with all these traffic jams. 我讨厌老是交通堵塞. 71. I'm sick and tired of... 我对……感到厌烦. I'm sick and tired of the same old routine every day. 我对每天同样的呆板的日常生活感到厌倦. [routine n.日常事物;常规] 72. I find it hard for me to... 我发现……对我来说很难. I find it hard for me to make a speech in public. 我发现在公众场合作演讲对我来说很难. 73. I hate to disagree with you, but... 我不想跟你有不同意见,但是……. I hate to disagree with you, but | think your view is impractical. 我不想跟你有不同意见,但我认为你的观点不切合实际. [impractical adj.不切实际的] 74.I have confidence in... 我相信…….俄对……有信心. I have confidence in winning the Crazy English speech contest. 我有信心赢得这次疯狂英语演讲比赛. 75. I have nothing to do with... 我与……无关. I have nothing to do with that man; I've never seen him before. 我与那个人一点关系都没有,我以前从来没见过他. 76. I have no experience in... 我在……方面没有经验. I have no experience in dealing with children.我在和孩子打交道方面没有什么经验. 77. I haven't (done)... for a long time. 我很久没有……了. I haven't played the piano for a long time.我芫妹挥械?智倭? 78. I insist that... 我坚决要求……. [宾语从句使用虚拟语气]│ I insist that you give me my money back.我坚持要求你把钱退给我. 79. I insist on (doing)...…我坚持……. I insisted on making him our coach. 我坚持要他做我们的教练. 80. I intend to...…我打算……. I intend to give him a surprise. 我打算给他一个惊喜. 81. I like nothing better than... 我喜欢……胜过任何东西.俄最喜欢……. I like nothing better than helping people. 我最喜欢帮助别人. 82. I never dreamed of...…我从未想过……. I never dreamed of meeting you here. What a coincidence! 我从未想过会在这里见到你.真是太巧了! [coincidence n.巧合;凑巧] 83. I prefer... to...…我喜欢……甚于……. I prefer working as a manager in a small company to working as a clerk in a big one. 我喜欢当个小公司的经理甚于在大公司做小职员. 84. I prefer to... rather than...我宁愿…...而不愿.…". I prefer to stay at home rather than go out 我宁愿呆在家里而不愿出去. 85. I really want to know... 我真的很想知道……. I really want to know how to improve my English pronunciation. 我真的很想知道如何改进我的英文发音. 86. I set my mind to do sth. / on sth.我下定决心……. I set my mind to believe, hope, and endure all things. 我下定决心对所有事情采取信任,希望和容忍的态度. 87. I sincerely hope that...我真诚地希望……. I sincerely hope that our friendship will last forever. 我真诚地希望我们的友谊天长地久. 88. I strongly advise you to... 我强烈建议你……. I strongly advise you to attend the Crazy English Summer Camp, and I'm sure you will get more than you expected. 我强烈建议你参加疯狂英语夏令营,我相信你的收获会比你想像的要多. 89. I suggest (that)... 我建议……. [宾语从句使用虚拟语气1 I suggest (that) you go there by yourself. 我建议你自己

2、讲述电表改装时，要抓住问题的症结所在，即表头内线圈允许通过的最大电流是有限制的(满偏电流Ig)，那么要测量较大的电压(或电流)怎么办？通过启发引导，学生能够提出电阻分压(或分流)，然后让学生讨论，推导出有关公式。教材结合具体例题，分别推出了分压电阻公式R＝URRg／Ug和分流电阻公式R＝IgRg／IR。

☆表头(G)改装成双量程电流表

[例1]如图所示，有一个表头G，满偏电流Ig=500 mA，内阻Rg=200 Ω，用它改装为有1 A和10 A两种量程的电流表，求R1、R2的阻值各为多大？

解析：当公共端与1 A端接入电路时，量程为I1=1 A，当公共端与10 A端接入电路时，量程为I2=10 A。

当公共端与1 A端接入被测电路时，电阻R1和R2串联，再与表头内阻Rg并联。由并联电路中的电流分配关系可得：R1+R2=Rg

代入Ig、I、Rg的数值得R1+R2=200 Ω　　　　 ①

当公共端与10 A端接入被测电路时，电阻R1与表头支路的电阻Rg+R2并联。由并联电路的特点可知：

Ig(Rg+R2)=(I2-Ig)R1

代入Ig、I2、Rg的数值，可得

R2+200 Ω=19 R1　　　　　　　　　　　　　　　　　　　　　 ②

由①②解得　　　　 R1=20 Ω， R2=180 Ω

［说明］对于I1=1 A的量程，G是它的表头，对于I2=10 A的量程，G与R2串联后相当于它的表头.

☆表头(G)改装成双量程电压表

[例2]如图所示，有一个表头G，满偏电流为Ig=1 mA，内阻Rg= 100 Ω，用它改装为有5 V和50 V两种量程的电压表，求R1、R2的阻值各为多大？

答案：R1=4.9 kΩ，R2=49.9 kΩ

解析：当公共端与5 V端接入被测电路时，量程为U1=5 V，当公共端与50 V端接入被测电路时，量程为U2=50 V.

由串联电路的电压分配关系可知：

R1=Ω=4900 Ω=4.9 kΩ

R2==49900 Ω=49.9 kΩ

★教学体会

1、本节课要重点讲清楚电流表的两个特性参数满偏电流Ig和表头电阻Rg的含义，以及相对应的电流表两端承受的最大电压值Ug＝IgRg的意义。

教师活动：让学生概括总结本节的内容。请一个同学到黑板上总结，其他同学在笔记本上总结，然后请同学评价黑板上的小结内容。

学生活动：认真总结概括本节内容，并把自己这节课的体会写下来、比较黑板上的小结和自己的小结，看谁的更好，好在什么地方。

点评：总结课堂内容，培养学生概括总结能力。

教师要放开，让学生自己总结所学内容，允许内容的顺序不同，从而构建他们自己的知识框架。

4、电压表和电流表

学生：请问：利用表头能够测量的最大电流和最大电压分别是多大？

教师：常用的电压表和电流表都是由小量程的电流表G(表头)改装而成的。

(投影)利用多媒体介绍表头的满偏电流Ig、内阻Rg和满偏电压Ug。

(1)满偏电流Ig

表头的线圈准许通过的最大电流很小，一般不超过几十微安到几毫安，这个电流值叫表头的满偏电流，用Ig表示。

满偏电流Ig：表头指针偏转到最大刻度时的电流。

［说明］如果通过表头的电流超过满偏电流Ig，不但指针指不出示数，表头还可能被烧坏。

(2)表头的内阻Rg

表头的线圈电阻一般为几欧到几百欧，这个电阻值叫做表头的内阻，用Rg表示。

内阻Rg：表头线圈的电阻叫做表头的内阻。

［说明］每个表头都有它的满偏电流Ig和内阻Rg，Rg和Ig是表头的两个重要参数。

教师：同学们能不能根据Ig、Rg概括出什么叫做满偏电压？

学生：表头通过满偏电流时，加在它两端的电压，这个电压值叫满偏电压，用Ug表示。

教师：满偏电流Ig、内阻Rg、满偏电压Ug三者之间有什么关系？

学生：据部分电路欧姆定律可知：Ug=IgRg

小结：表头G的满偏电压Ug和满偏电流Ig一般都比较小，测量较大的电压和较大的电流时，需要把小量程的表头G加以改装。

(投影)例1 电流表改装成电压表

(投影)例2 电流表改装成大量程电流表

教师：在初中我们已经学过有关串联和并联的知识，这节课我们要深入研究串并联电路中各部分的电流、电压及电阻的关系。