Determining the functions of play is difficult because the functions may be long-term, with beneficial effects not showing up until the animal's adulthood.

定义玩耍的功能是困难的，因为这些功能可能是长期性的，其积极影响要到动物成年后才会显现。

youdao

Not only will those skills be actually integrated into the curriculum but they will be very important to have in the future because they are difficult to automate.

因为这些技能很难自动化，它们不仅会被整合到课程中，在未来也将变得非常重要。

youdao

If you are talking about a subject you know well, as I've just advised, prepared, preparing the speech itself should not be too difficult.

如果你正在谈论一个你很熟悉的话题，就像我刚才建议的，做好准备；准备演讲本身应该不是太难。

youdao

I did not want them to be difficult or to get in my hair while I was working on the computer.

VOA: special.2009.05.03

I'm not going to have you work long hours on difficult problems to be submitted and then graded.

我的作业不会让你们花费大量的时间,去钻研很难的问题，然后交上来让我打分。

麻省理工公开课 - 固态化学导论课程节选

The reason that's going to be the strategy is that voting's not going to be difficult.

策略是这个的原因是,投票并不难

耶鲁公开课 - 博弈论课程节选

But being heard over the din of Labour's death throes - Nick Clegg's words not mine - will be difficult if not nigh on impossible.

BBC: Challenge for Clegg despite tax victory

However, he hoped it would not be too difficult to get people visiting again.

BBC: Zoo reopens after disease scare

It would not be difficult to conceal a weapon in a shoulder bag, he says.

BBC: Venner suicide at Notre-Dame 'political' - Le Pen