打井的英文：
to dig a well

The farmers drove wells to water the crops.
农民打井灌溉庄稼。

They are digging at physics.
他们在钻研物理学。

What are they digging for?
他们正在探究什么?

To dig or hollow out.
挖洞，挖空

The detectives are digging into this whole business.
侦探们正在彻底地调查这整件事情。

It is not easy to dig out the past.
发掘过去的历史是不容易的。