这是一个非常艰巨的事业。

That's a very daunting undertaking.

youdao

假设最近的模型表明，温室气体是一项须长期治理且日益艰巨的事业的话，那么，这样的新闻将令人耳目一新。

Considering that recent models indicate greenhouse gasses are going to be a long-term atmospheric issue to clean up after, this news comes as a bresh of fresh air.

youdao

我们的艰巨任务是要激励那些投票者并鼓励他们加入我们的事业。

Our challenge is to motivate those voters and inspire them to join our cause.

《柯林斯英汉双解大词典》