has been down是什么时态
have been down是过去完成时的被动语态。
We have been down here 40 years.
我们搬到这里已经40年了。
This may have been down to tension.
这也许是因为紧张。
Most of the older buildings have been torn down and replaced by modern monstrosities.
绝大部分旧建筑已被拆除，取而代之的是奇丑无比的\'现代建筑物。
We have been beaten in some games which we should have won hands down.
我们曾经在一些本应轻易取胜的比赛中落选。
They have been cutting down the trees and bulldozing the land.
他们正砍倒树木，推整土地。