When the rig sank, the riser broke near the top while remaining attached to the blowout preventer at the bottom.

当钻井平台下沉时，立管在顶部附近的地方断裂，同时另一端仍与底部的防喷器相连。

Four required per backflow preventer.

每个防回流阀需要四个。

What do we use to control the blowout preventer?

我们用什么来管制封井器呢？

We do not use this valve to control the blowout preventer.

我们不用这个凡尔管制防喷器。

All spare parts of the blowout preventer are kept in that room.

所有的防喷器配件都得保存在那间房子里。