条件句类型1的基本形式在这里时态的变化遵循通常的规律：
He said，‘If I catch the plane I’ll be home by five.’
他说：“我如果能赶上这班飞机，5点钟以前就可以到家了。”相当于：
He said that if he caught the plane he would be home by five.
他说他如果能赶上那班飞机，5点钟以前就可以到家了。
条件句类型2的基本形式在这里时态不变：
‘If I had a permit I could get a job，’he said.
他说：“如果我有许可证就能找到工作。”相当于：
He said that if he had a permit he could get a job.
他说如果他有许可证就能找到工作。
条件句类型3的基本形式在这里时态不变：
‘If she had loved Tom，’ he said，‘she wouldn’t have left him.’
他说：“如果她喜欢汤姆，就不会离开他。”相当于：
He said that if she had loved Tom she wouldn’t have left him.
他说如果她喜欢汤姆的话就不会离开他。
关于if从句+命令或者要求在间接引语中的例句：
He said，‘If you have time wash the floor.’
他说：“如果你有时间，擦一擦地板。”
He said，‘If you have time would you wash the floor?’
他说：“如果你有时间，你能擦一擦地板吗?”相当于：
He told/asked me to wash the floor if I had time.
他叫/要我有时间的话擦一擦地板。
He said that if I had time I was to wash the floor.
他说如果我有时间的话就擦一擦地板。
‘If you see Ann ask her to ring me，’he said.
他说：“如果你遇到安，叫她给我打个电话。”相当于：
He said that if I saw Ann I was to ask her to ring him.
他说如果我看到安，告诉她给他打个电话。(这里如用 ask+不定式结构就变得很拗口，也不十分清楚。)
Peter(on phone)： If you miss the last bus get a taxi.
彼得(在打电话)：如果你们误了末班车，就雇一辆出租汽车。
Peter says that if we miss the last bus we are to get a taxi.
彼得说如果我们误了末班车就雇一辆出租汽车。
关于在间接引语中的if从句+劝告的表示法：
‘If you feel ill，’she said，‘why don’t you go to bed?’/‘…you’d bet- ter go to bed.’
她说：“如果你感到不舒服为什么不躺一下?”/…你最好上床休息。
She advised me to go to bed if I felt ill.
她劝我，如果感到不舒服了就上床休息。
She said that if I felt ill I’d better/I should go to bed.
她说如果我感到不舒服了我最好/应当上床休息。
‘If I were you I’d stop taking pills，’she said.
她说：“如果我是你的话，我就停止吃药。”相当于：
She advised me to stop taking pills.
她劝我停止吃药。
if从句+疑问句结构在间接引语中通常把if从句置于句末：
‘If the baby is a girl what will they call her?’ he wondered.
他心里想：“如果生的是个女孩，他们会给她取个什么名字?”相当于：
He wondered what they would call the baby if it was a girl.
他心里想，如果生的是个女孩，他们会给她取个什么名字。
‘ If the door is locked what shall I do?’ she asked.
她问道：“如果门锁了我该怎么办?”相当于：
She asked what she would do if the door was locked.
她问如果门锁了她该怎么办。
