Their problem was to bind the black powder together again so it would be hard enough to serve as a writing instrument.

它们的难题是如何重新组合这些黑色的粉末，使它成为有足够硬度的书写工具。

youdao

It will never return to its glory days of 1999, it will be hard enough to keep Google and Facebook from stealing AD dollars from big advertisers.

它再也无法重现1999年的光辉岁月，要阻止谷歌和Facebook从大型广告客户手中抢走大量生意，难如登天。

youdao

So far, machines have a pretty hard time emulating creativity, arbitrary enough not to be predicted by a computer, and yet more than simple randomness.

到目前为止，机器在模仿创造力方面有相当困难的时间，它们的随机性足以让计算机无法预测，但也不仅仅是简单的随机性。

youdao

It can be hard enough to determine the authenticity and provenance of a work through the regular channels.

FORBES: Jackson Pollock or Not? Avoiding Fakes in the Art World

It was disappointing for Durham with all the rain over the first two days but for us to be able to push hard enough to get a result was a fantastic effort and proves we are playing some excellent cricket.

BBC: Paul Collingwood column

Time is arguably the most valuable asset of every entrepreneur and can be hard to find enough time in the day to do everything you need to do keep your business running.

FORBES: Dissipated Energy Takes Time Away From Building Your Business