2．在静电场中，将一个点电荷从a点移到b点，其电势能的变化为零，则( 　)

A．该点电荷一定沿等势面移动

B． a、b两点的场强一定相等　　 C． a、b两点的电势一定相等

D．该点电荷所受的电场力方向与其移动方向始终相互垂直

1．如图所示，质量相等的A、B两物块置于绕竖直轴匀速转动的水平圆盘上，两物块始终相对于圆盘静止，则两物块(　 )

A．线速度相同　　　　　　　　 B．角速度相同

C．向心加速度相同　　　　　　 D．向心力相同

2．地点状语的变化

　 当直接引语变间引语时，地点状语here通常变为there。但如果说话人所在地点就是引述人所在地点，那么仍然使用here.

　 Come here, please, he said.

　 → He asked me to come here. 他叫我到这里来。(引述人地点不变)

　 → He asked me to go there. 他叫我到那里去。(引述人地点发生变化)

　 Here she burst out into a flood of tears, he said to me.

　 → He told me that she had burst out into a flood of tears there. 他告诉我说，谈到那个地方她就放声大哭了起来。

1．时间状语的变化

　 He said, I spoke to them yesterday.

　 → He said that h had spoken to them the day before. 他说他前一天跟他们讲过话了。

　 The student said, We have learned about 3,000 English words so far.

　 →　 The student said that they had learned about 3,000 English words by then. 那学生说到那时为止他们已学会了3,000个英语单词。

3．指示代词的变化

　 直接引语中的指示代词

　 this

　 these

　 间接引语中的指示代词

　 that

　 those

　 She said, This is the house in which Lu Xun once lived.

　 → She said that that was the house in which Lu Xun had once lived. 她说那是鲁迅曾经住过的房子。

　 I bought these flowers for you, Jane said.

　 Jane said that she had bought those flowers for me. 简说那些花是她为我买的。

　 I grow these tomatoes myself, he said.

　 → He aid that he grew those tomatoes himself. 他说那些胡萝卜是他自己种的。

C．　 时间和地点状语的变化

2．物主代词的变化

　 You should not overlook your fault, Mum said to me.

　 → Mum told me that I should not overlook my fault. 妈妈对我说我不应该忽略我的缺点。

　 The two boys said, We have lost our dog.

　 → The two boys said they had lost their dog. 这两个男孩说他们的狗丢了。

1．人称代词的变化

　 ①当主句的主语是第一人称时，引语中的人称代词不变。

　 I said, You did quite well in the exam yesterday.

　 → I said that you had done quite well in the exam the day before.我说你那天考得不错。

　 ②直接引语中主语是第一人称时，在改为间接引语时，其人称与主句中的主语的人称一致。

　 He said to Tom, I'll do my best to catch up with others.

　 → He told Tom that he would do his best to catch up with others.　 他告诉汤姆他将尽他所能赶上其他人。

　 ③直接引语中主语是第二人称时，在改为间接引语时，其人称和主句的宾语相一致。

　 He said to her, Where did you put the glasses

　 → He asked her where she had put the glasses. 他问她，她把杯子放哪儿了。

　 提示：

　 如果主句中无宾语，应根据语境或想象，自添适当的宾语；如果直接引语中有呼语，则将其改为间接引语的宾语。

　 Mother asked, Where have you been

　 → Mother asked me where I had been. 母亲问我去哪儿了。

　 Why are you late again, John the teacher asked.

　 → The teacher asked John why he was late again. 老师问约翰为什么他又迟到。

　 ④直接引语中主语是第三人称时，在改为间接引语时不发生变化。

　 He said to Tom, She can help them.

　 → He told Tom that she could help them. 他告诉汤姆她能够帮助他们。

2．情态动词的变化

　 情态动词在间接引语中都可以改为过去式，must表示必、推测、禁止等意思时，可不变；表示必须时可不变，也可用had to 或would have to。

　 The senior said, All men must die.

　 → The senior said that all men must die. 那老者说人总是要死的。

　 She said, I must go to see the doctor tomorrow afternoon.

　 → She said she must/would have to go to see the doctor the next afternoon. 她说第二天下午她一定得去看医生。

　 He said to me, We used to go there every year.

　 → He told me that they used to come here every year. 他对我说他们过去每年都来这里。(used to在间接引语中不变)

B．　 代词的变化

　 直接引语变为间接引语时，间接引语中的动词时态、人称代词、物主代词、指示代词、时间和地点状语以及主谓语词序往往要作相应的变化。

A．　 时态的变化

1．时态的变化

　 ①现在时间推移到过去时间

　 直接引语中的时态

　 一般现在时

　 现在完成时

　 现在进行时

　 现在完成进行时

　 间接引语中的时态

　 一般过去时

　 过去完成时

　 过去进行时

　 过去完成进行时

　 The old man said, I have lived in this street since 1960.

　 →The old man said that he had lived in that street since 1960. 那老人说他自从196年起就住在那条街上了。

　 He said, Is it raining

　 → He asked if it was raining. 他问是不是正在下雨。

　 ②过去时间推移到过去的过去

　 直接引语中的时态

　 一般过去时

　 过去完成时

　 过去进行时

　 间接引语中的时态

　 过去完成时

　 过去完成时(不变)

　 过去完成进行时或不变

　 She said to me, I wrote a letter to my parents three days ago.

　 →She told me that she had written a letter to her parents three days before.她告诉我她三天前已给她母亲写了一封信。

　 What were you doing at seven p.m. yesterday he asked

　 → He asked me what I was doing at seven p.m. the day before. 他问我前一天晚上七点在干什么。

　 ③将来时间推移到过去将来时间

　 直接引语中的时态

　 一般将来时

　 Is/am/are going to do

　 Is/am/are to do

　 间接引语中的时态

　 过去将来时

　 Was/were going to do

　 Was/were to do

　 He said, We shall get ready by eight o'clock.

　 →He said that they could get ready by eight o'clock. 他说他们将在8点前准备好。

　 We are to meet at the school gate, she said to me.

　 → She told me that they were to meet at the school gate. 她告诉我他们约定在校门口见面。

　 ④间接引语中保持原来时态不变

　 在下列情况下，间接引语中的谓语动词时态可以保持不变。

　 a. 主句为现在时或将来时，间接引语的时态保持不变。

　 He thinks, She will be back in a month.

　 → He thinks she will be back in a month. 他想她将在一个月后回来。

　 He says, I have accepted her invitation.

　 He says he has accepted her invitation. 他说他已接受了她的邀请。

　　比较：

　 间接引语中的谓语动词时态对比。

　 Sarah said to me, I have two brothers.　 莎莎对我说：“我有两个弟弟。”

　 Sarah told me that she has two brothers.　 莎莎告诉我说她有两个弟弟。(说话才认为这情况是真实的)

　 Sarah told me that she had two brothers.　 莎拉告诉我说她有两个弟弟。(说话者对此没有什么把握)

　 b. 间接引语表示的是现在的习惯动作、科学真理、客观事实、格言等。

　 The geography teacher said to the students, The earth moves round the sun.

　 → The geography teacher told the students that the earth moves round the sun. 老师告诉学生地球围绕太阳转。

　 He said, Every dog has his day.

　 → He said that every dog has his day. 他说是人皆有出头日。

　 c. 间接引语中动词表示的动作说话时仍在进行或状态仍然存在，时态可保持不变。

　 He said, The window is broken.

　 → He said that the window is broken.他说玻璃窗碎了。

　 Just now Brown said, My son is ill today.

　 → Brown told me just now that his son is ill today. 布朗刚才告诉我说，他儿子今天病了。

　 d. 间接引语中有明确的过去时间状语，仍可用一般过去时，不必改为过去完成时。

　 The girl said, I was born in 1978.

　 → The girl said that she was born in 1978.那女孩说她生于1978年。

　 She said, My teacher was busy yesterday.

　 → She said that her teacher was busy yesterday. 她说她老师昨天很忙。

2．有些感叹句可以根据原句的意思，采用适当的动词变为陈述句，不需用间接宾语来转述。

　 Help! he cried. 他喊到：救命啊！

　 → He called for help. 他大声呼救。

　 What terrible weather it is! he said. 他说：多么糟糕的天气！

　 → He complained about the terrible weather. 他抱怨这糟糕的天气。

　 Happy Christmas! he said. 他说：圣诞快乐！

　 He wished me a happy Christmas. 他祝我圣诞快乐。