您要查找的是不是：
- A little crack detracts from the value of the vase. 小小的裂痕减损那个花瓶的价值。
- The marchers jumped off at the crack of dawn. 行军队伍在破晓时出发了。
- The riot police started to crack down on them. 防暴警察开始对他们采取镇压行动。
- You'll crack up if you go on working so hard. 你继续这样拚命干下去，身体会吃不消的。
- Friction causes a rolling ball to stop finally. 摩擦力使滚动的球最终停了下来。
- Have another crack at solving this puzzle. 再试一试把这个难题解决了吧。
- Constant friction wore out the heels of my shoes. 不断的摩擦磨损了我的鞋跟。
- Friction between two sticks can create a fire. 两个棍棒相互摩擦能起火。
- She made a crack about his fatness. 她取笑他肥胖。
- There is a crack in this window. 这扇窗户上有个裂纹。
- She got up at the crack of dawn. 天刚亮她便起床了。
- Mary found knitting a hard nut to crack. 玛丽发现编织并非易事。
- In the absence of friction belted machinery would not be used. 没有摩擦力，皮带传动的机器就无法使用。
- He was the tough guy, the big shot, who gave orders with the crack of a whip. 他是个威风凛凛发号施令的强悍的家伙，是个大人物。
- I'd do anything to see you crack a smile. 为了博得你的一笑，我情愿做任何事。
- Her foot wedged in the narrow crack. 她的脚卡在那狭缝里了。
- Close examination revealed a crack in the vase. 花瓶经仔细检查发现有裂缝。
- It was then a hard nut to crack. 在那时是一桩很棘手的事。
- It was then a tough nut to crack. 在那时是一桩很棘手的事。
- Matches are lighted by friction. 火柴由摩擦而生火。
