She said: "This computer is more powerful than ours."
She said that computer was more powerful than theirs.

2)各种时态的变化
例如：
George said: " Betty is sleeping."
George said Betty was sleeping.

He said: "The meeting has been canceled."
He said the meeting had been canceled.

She said: "The road is blocked."
She said the road was blocked.

She said: "I was not there."
She said she had not been there.

She said: "I will send you a present."
She said she would send me a present.

They said: "We will have finished this project by the end of this month."
They said they would have finished this project by the end of this month.

3) 注意：直接引语变间接引语时，时态不作相应变化的情况：
a）　直接引语表示科学真理、客观事实、现在习惯动作和谚语格言等。　
The teacher told the students: "The sun rises in the east and sets in the west."
The teacher told the students that the sun rises in the east and sets in the west.
b) 直接引语中的would, should, ought, might, had better,　used to 等一般不变。
Peter said: "I might try my luck."
Peter said he might try his luck.
c) 直接引语中的谓语动词为虚拟语气时不变。例如：
She said: "It is time that I went home."
She said it was time that she went home.
d) 直接引语中无过去形式的情态动词。
She said: "You mustn't drink before driving."
She said I mustn't drink before driving.

4) 因无过去形式的情态动词有不同的情态含义，变为间接引语时，可换用其它词。如must表示"必须"时，在间接引语中可有几种表示法: must, had to, would have to ; 但如 must 在句首要用had to 表示。例如：
He said: "You must hand in your exercises."
He said we must/had to/would have to hand in our exercises.

"Must we hand in our exercises?" they asked.
They asked whether they had to hand in their exercises.

5) 直接引语中表示的状态或动作引述时仍在继续时，不变。
She said: "I am a retired teacher."
She said she is a retired teacher.

6)"过去的过去"时间概念已经很清楚以及将来时间很明确，变为间接引语时，人称的变化有时会引起动词词形的变化。
She said: "I am a retired teacher."
She said she is a retired teacher.

The teacher said: "I shall visit Hong Kong in 2000."
The teacher said he will visit Hong Kong in 2000.

2. 词缀

前缀hydro-意为containing or concerning water, "含水的"或"与水有关的"：
hydrocarbon 碳氢化合物 hydroelectric 水力发电的
hydroplane 水面快艇 hydraulics 水力学
前缀 equa- 含"平等，相等"之意：
equal 相同的，相等的 equalize 使平等，使对等
equality 平等 unequal 不平等的
equate 使等量，使相等 equation 方程式，等式
equator 赤道（把地球等分）
由equa--- -equi- 同义前缀：
equidistant 等距离 equilateral 等边的
equitable 公正的，公平的 equity 公平，公正
equivalent 相等的，相当的 equivalence 相等，等值

3. 词性转换

conversion 词性转换是英语构词的主要方法之一，因此也是我们记忆单词的一个有效途径。通过一个词词性的转换，构成一个新的单词，也使这个词本身的意义丰富起来，加深了我们的理解。
man n.男人- v. 备以人员
surface n. 表面- v. 露出水面；出现
bus n. 公共汽车- v. 用公共汽车接送
cycle n. 自行车- v. 骑自行车
run v. 跑- n. 跑步；短程旅行
want v. 想要- n. 穷困，贫乏
wear v. 穿，戴- n. 用损，磨损
fall v. 跌倒- n. 跌落，堕落

4. 复合形容词

man-made 人造的
man-made satellite 人造卫星
a man-made catastrophe 人为的灾祸
travel-worn 旅行疲乏的
poverty-stricken 贫困不堪的