1.They haven't finished the job yet.
2. She might have come if she hadn't been so busy.
3.I have an apple.
4. I had dinner with him yesterday.
5.I have a cold.
1. have +过去分词，构成完成时态。如：
He has left for Japan. 他已去了日本。
We’ve just done the washing-up. 我们刚洗完碗碟。
Poor Jim has just had an accident. 可怜的吉姆刚出了个事故。
I have had this car for three years. 这辆汽车我已用了3年了。
By the end of last month, they had finished the work. 上月未他们就已经完成了工作。
2. have + been +现在分词，构成完成进行时。如：
I have been studying English for 8 years. 我学英语已达八年了。
The children have been having a lot of run. 孩子们一直玩得很开心。
We had been doing business with each other for years before we quarreled. 在吵翻之前，我们多年来在业务上一直来往。
By this time next year, we will have been doing business with each other for 20 years. 到明年这时候，我们的业务住来就满20年了。
I woke up—I had been having a bad dream. 我醒了，我做了个噩梦。