apprehend|apprehended|apprehending

警方在机场逮捕了一名逃犯。

The police ___apprehended a fugitive at the airport.

警察正在逮捕那个偷钱包的小偷。

The officers are ___apprehending the thief who stole the wallet.

他很快领会了这个数学概念的基本原理。

He quickly ___apprehended the basic principles of this math concept.