这份工作很辛苦，需要长时间集中注意力。

This job is really ___hard because it requires long hours of concentration.

这块木板很硬，很难掰弯。

This wooden board is so ___hard that it's difficult to bend.

冬天的暴风雪让登山变得异常艰难。

The winter blizzard made climbing the mountain extremely ___hard.

他用力敲门，整栋楼都能听到。

He knocked on the door so ___hard that the whole building could hear it.

听到这个消息对我来说很难接受。

It's ___hard for me to accept this news.