hard / hardly

1. hard 意为“艰苦的”， 可用作形容词或副词。

2. hardly 意为“几乎不”， 用作副词，表示否定意义。

hard-working / hard work / work hard

1. hard-working 意为“工作努力的；辛勤的”， 形容词

2. hard work 意为“辛苦的工作”， 名词短语，hard 是形容词，修饰不可数名词 work

3. work hard 意为“努力工作”， 动词短语，hard是副词，修饰动词work

全部

1·All five men are hard workers.

五个人全都工作努力。《牛津词典》

2·He worked hard for his dough.

他为了赚钱而努力工作。《柯林斯英汉双解大词典》

3·Hard work never hurt anyone.

努力工作绝无害处。《牛津词典》

4·That's a very hard question.

那是个很难的问题。《柯林斯英汉双解大词典》

5·It's pretty hard to explain.

这事很难解释清楚。《牛津词典》

6·I find that hard to believe.

我对此感到难以相信。《牛津词典》

7·She was a hard taskmaster.

她是个严厉的工头。《牛津词典》

8·I have to work hard today.

今天我得努力工作。《牛津词典》

9·I only succeeded through hard work.

我就是因为努力工作才成功的。《柯林斯英汉双解大词典》

10·Our water is very hard.

我们的水很硬。《牛津词典》

努力的

1·I only succeeded through hard work.

我就是因为努力工作才成功的。《柯林斯英汉双解大词典》

2·He was a glutton for hard work.

他是个酷爱努力工作的人。《柯林斯英汉双解大词典》

3·She tried extra hard.

她特别努力。《牛津词典》

4·If you study hard, you can make the roll of honour.

如果你努力学习，你就能上荣誉名册。《柯林斯英汉双解大词典》

5·The mechanics work hard to keep the helicopters airworthy.

机修工们为了保障直升机的适航性而努力工作着。《柯林斯英汉双解大词典》

努力地

1·Richard is already working very hard.

理查德已经很努力地工作了。

2·They work very hard to build their nests.

为了筑巢，牠们非常努力地工作。

3·Working hard isn't the same as working smart.

聪明地工作和努力地工作不同。

4·You tried very hard to conceal it, did you not?

你很努力地想隐藏它，不是吗？

5·If it was capable of some astonishing progress, there was another sense in which it had to run very hard just to stay on the spot.

如果它有能力取得一些惊人的进步，在另一种意义上，它必须非常努力地奔跑，才能保持原地不动。

硬

1·The sun had baked the ground hard.

太阳把地面晒硬了。《牛津词典》

2·Our water is very hard.

我们的水很硬。《牛津词典》

3·Joe has a bad back so we have a hard bed.

乔的背不好，所以我们睡硬板床。《柯林斯英汉双解大词典》

4·During the dry season the land is rock hard.

土地在旱季硬如岩石。《柯林斯英汉双解大词典》

5·She swallowed hard and told him the bad news.

她硬下心把坏消息告诉了他。《牛津词典》

很难

1·It's hard not to be cynical about reform.

很难对改革不持怀疑态度。《柯林斯英汉双解大词典》

2·It is hard to believe that she's only nine.

很难相信她只有九岁。《牛津词典》

3·It's always hard to speculate about the future.

推测未来总是很难的。《柯林斯英汉双解大词典》

4·She found it hard to live up to his high ideals.

她觉得很难达到他的高标准要求。《牛津词典》

5·It's been hard to get a steady fix on what's going on.

一直很难对正在发生的事情有一个清楚可靠的了解。《柯林斯英汉双解大词典》

困难的

1·It's not as hard as I thought.

这没有我想象的那么困难。《牛津词典》

2·Because of her deafness she was hard to make conversation with.

由于她失聪，和她交流很困难。《柯林斯英汉双解大词典》

3·They were hard times and his parents had been struggling to raise their family.

那是困难时期，他的父母一直挣扎着养家糊口。《柯林斯英汉双解大词典》

4·He had to feed his family on the equivalent of seven hundred dollars a month and, with five mouths to feed, he found this very hard.

他每月不得不用相当于700美元的钱来养家，5张嘴等着吃饭，他觉得很困难。《柯林斯英汉双解大词典》

5·Heat makes it hard to breathe.

过高的热度导致呼吸困难。

艰苦

1·He was unaccustomed to hard work.

他不习惯艰苦工作。《牛津词典》

2·In Africa life can be hard.

在非洲生活可能是艰苦的。《牛津词典》

3·We've got a lot of hard work ahead.

我们往后还有很多艰苦工作要做。《牛津词典》

4·She's had a hard life.

她一生艰苦。《牛津词典》

5·Bringing up a baby is undeniably hard work.

抚养一个孩子无可否认地是项艰苦的工作。《柯林斯英汉双解大词典》

辛苦

1·I'm under no illusions about what hard work this will be.

对于这项工作的辛苦，我从不存错误的幻想。《牛津词典》

2·You must relax, don't work too hard.

你必须放松，不要工作得太辛苦。

3·I'm worn out by the hard work.

这辛苦活使我筋疲力尽。

4·You've really done a hard day's work.

今天你们可够辛苦了。《新英汉大辞典》

5·He has worked very hard recently, so he deserves a week's holiday.

前一段他很辛苦，现在休息一星期是应该的。《新英汉大辞典》

难

1·The Geography paper was hard.

地理试题难极了。《牛津词典》

2·In fact, cooking dinner is not that hard.

其实，做顿晚餐也没那么难。

3·It's easy to get into, but hard to get out of.

进入容易，退出难。

4·It would not be so hard, if he were like other mortals.

如果他和别人一样，事情就不会那么难了。

5·I had no idea that being an American would ever be this hard.

我不知道做一个美国人会这么难。

坚硬

1·He shuffled his feet on the hard wooden floor.

他拖着脚走在坚硬的木地板上。《柯林斯英汉双解大词典》

2·Teeth have a hard surface layer called enamel.

牙齿有一层叫做釉质的坚硬表层。《牛津词典》

3·The substance polymerizes to form a hard plastic.

这种物质聚合形成坚硬的塑料。《牛津词典》

4·Although the coral looks hard, it is very delicate.

虽然那珊瑚看起来坚硬，它其实非常易碎。《柯林斯英汉双解大词典》

5·The fossils at Dinosaur Cove are embedded in hard sandstone.

恐龙湾中的化石嵌在坚硬的砂岩中。《柯林斯英汉双解大词典》

(1)hard work努力工作；繁重的工作

(1)work hard努力学习；辛勤工作

(1)study hard努力学习

(1)working hard努力工作

(1)hard on严厉对待

(1)hard disk硬盘