拓展：have been，has been， had been

　　1.解釋：have/has/had+been 都是完成時。

　　2.區別：has/have been是現在完成時,has用于第三人稱單數; had been過去完成時,跟前者相比,比前者更為過去;

　　3.例句：

　　（1）He has been doing this work for a period of time.

　　（2）I want to have this book.

　　（3）Have you pass the math exam?

　　（4）Do you ever had a thought that you can win this game?