have you been to beijing before? 你以前来过北京吗?

　　have you been to beijing before?

　　你以前来过北京吗?

　　yes, i have. many times.

　　是的，来过。来过很多次。

　　really. you must know it quite well.

　　是吗？你一定非常了解北京。

　　well, this is my sixth visit, i think. i get to know it a little bit more each time.

　　哦，我想这是第六次来北京了。我一次比一次更了解它。

　　six times! that’s a lot. it’s nearly your home city!

　　六次！不少啊。差不多成了你的家乡了！

　　如果问某人在过去是否做过某事，你可以说：have you been to beijing before? /你以前去过北京吗? ;

　　have you seen the great wall? / 你见过长城吗?

　　you must know it quite well. /你一定对它非常了解。当你非常确定某事时，你可以用下面这个表达法：

　　you must . . . / 你一定 . . . ；例如, 在某人忙碌了一天之后说:

　　you must be tired / 你一定累了。