But I want to end by mentioning the hard problem as it is known now.

最后，我想再讲一个众所周知的难题。

youdao

He is clever enough to work out the hard problem.

他很聪明，能自己解出这道难题。

youdao

He is clever enough to work out the hard problem.

他很聪明，能自己解出这道难题。

youdao