"Mr. Bullen gets up and begins to walk up and down again.

布伦先生起床，又开始来回走动。

This is where I used to walk up and down and wonder and wonder.

我过去常常在这里走来走去，思考这，思考那。

Walk up and down the hotel halls.

在宾馆大厅里来回的走走。

Walk up and down for the allotted time.

在规定的时间里上下楼梯。

I saw her walk up and down in the classroom.

我看见她在教室里走来走去。