She said, "I am very happy to help you."→She said that she was very happy to help you.
2. 直接引语是一般(选择/反意)疑问句，变成间接引语时，由连词whether或if 引导。例如：
He asked me, "Do you like playing football?"→He asked me if/whether I liked playing football.
注意：大多数情况下，if和whether 可以互换，但后有or not,或在动词不定式前，或放在介词后作连接词时，一般只用whether。例如：
She asked me whether he could do it or not.
He hesitated about whether to drive or take the train.
3. 直接引语是特殊疑问句，变成间接引语时，由相应的疑问词who, whom, whose, how, when, why, where 等引导。例如：
My sister asked me, "How do you like the film?"→My sister asked me how I liked the film.
4. 直接引语是祈使句，变成间接引语时，把动词原形变成动词不定式，并在动词不定前加tell, ask, order 等的宾语。例如：
The captain ordered, "Be quiet."→The captain ordered us to be quiet.
My teacher asked me, "Don't laugh."→My teacher asked me not to laugh.
The teacher said "The earth goes round the sun."
→The teacher said that the earth goes round the sun.
He said to me, "I was born in 1973."
→He told me that he was born in 1973.
He said, "I'm a boy, not a girl."
→He said that he is a boy ,not a girl.
The girl said, "I get up at six every morning."
→The girl said that she gets up at six every morning.
(5)如果直接引语中含有since, when, while 引导的表示过去时间的状语从句，
He said to me, "I have taught English since he came here ."
→He told me that he had taught English since he came here.
(6)如果直接引语中含有情态动词 must, need, had better以及情态动词的过去式could, might, should, would,
The teacher said to me . "You must pay more attention to your pronunciation."
→The teacher told me that I must (have to ) pay more attention to my pronunciation.
He said , "I could swim when I was only six ."
→He said that he could swim when he was only six.
He asked Lucy, "Where did you go?"→He asked Lucy where she went.
Tom said, "What do you want, Ann?"→Tom asked Ann what she wanted.