But the acquisition of radioactive material for a so-called 'dirty bomb,' which is radioactive material that is dispersed with a conventional explosive device, that is not that challenging.

VOA: standard.2009.05.01

He makes it clear that utility is the only standard of morality, in his view, so he's not challenging Bentham's premise. He's affirming it.

明确指出功利是道德的唯一标准，在他看来，他并没有质疑边沁的前提，而是肯定此观点。

耶鲁公开课 - 公正课程节选

We're still close enough to the summer that the air is not just filling us up with extra static electricity, so it's a little more challenging here.

我们现在离夏天更近了,这样空气中不总是,充满额外的静电，所以这时做实验,会有一些挑战性。

麻省理工公开课 - 化学原理课程节选

Well, crossword puzzles aren't a very deep subject, and we might wonder whether or not we would do better if we were engaged in something more mentally challenging than that.

填字游戏不算很深奥的东西，我们也不知道自己能否做得更好,如果我们去做,比填字游戏更富挑战性的事情。

耶鲁公开课 - 死亡课程节选

So that's not too challenging.

那个挑战性不是很强

耶鲁公开课 - 聆听音乐课程节选