This is a hard job.; The task is arduous.

这个任务很吃重。

《新英汉大辞典》

The task is arduous; besides, there's not much time.

任务艰巨，同时时间又很紧迫。

《新英汉大辞典》

Although the task is arduous, it can still be finished on time.

任务虽然很艰巨，但还是可以按时完成。

youdao

Harvesting stem cells from the body is an arduous task, in part because so few of the cells exist in people.

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All that said, this is not a difficult task, although it is arduous: slow and steady wins the race, or at least gets you on the ballot.

FORBES: Why Is It So Difficult To Qualify For the Virginia Presidential Primary Ballot?

However, this leaves the MPAA with the arduous task of prosecuting single users one at a time, a prospect that is both expensive and, as some of the musicians complaining about Napster are finding, bad for public relations.

FORBES: Gnutella Could Make Moviemakers Cry