The posts have to be set in concrete.

这些柱子必须用混凝土固定。

They had lain on sleeping bags on the concrete floor.

他们就躺在铺在混凝土地面上的睡袋上。

...concrete barriers.

混凝土壁垒

He merely cleared and concreted the floors. [VERB noun]

他只是把地面清理之后浇上了混凝土。

He had no concrete evidence.

他没有确凿的证据。

There were no concrete proposals on the table.

没有具体的提议可供讨论。

I must have something to tell him. Something concrete.

我必须告诉他点什么，必须是具体的东西。

...using concrete objects to teach addition and subtraction.

用实物来教加减法

As Mr Blunkett emphasised, nothing is yet set in concrete.

正如布伦基特先生所强调的，一切都还没有定下来。