Underground work is slow going, because construction crews often unearth mosaics, frescos, marble.

地下工进展缓慢，因为施工人员经常挖掘出镶嵌画、壁画和大理石。

Well, perhaps you haven't been looking hard enough.

可也许你还没有下工夫去。

They are coming from work in the yard.

那都是从船坞下工的工人们。

Somebody went to a lot of time and expense.

有人为此很下工夫。

" And you ought to put in a bit more effort on your Occlumency from now on."

“从你要多下工夫练大脑封闭术。”

Sometimes after work, I go to the park and feed the birds.

下工后我去公园喂鸟。

We haven't even completed that substructure floor yet.

地下工的地面尚未完工。

And thus there would be the potential of underground engineering that was done by those of a different scientific period of time.

因此，就有可能存由不同科学时期的人进行的地下工。