The hard bone has dulled up the knife blade.

这硬骨头把刀刃弄钝了。

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Their skeletal structure is extremely flexible, as it is made of cartilaginous material rather than hard bone.

其骨骼构造非常柔韧，因为他们没有硬骨，只有软骨。

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She was honest and hard-working, and didn't have an unkind bone in her body.

她诚实勤劳，身上没有一点儿不好的气质。

《牛津词典》

Then,a hard cast may be put around the area of the break to hold the bone in place while it heals.

VOA: special.2009.02.04

Biolase's Waterlase system uses a patented combination of water and lasers to precisely cut hard tissues (bone and teeth) and soft tissue (gums) with minimal damage to surrounding areas.

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The patient also received lower eyelids, upper lip, skin, muscles, bone, hard palate, arteries, veins and nerves.

CNN: Face transplant patient regains self-confidence

The recent hot spell had left the course fast-running and bone-hard before the rain took the edge off for the first round.

BBC: SPORT | Golf | Last-hole eagle sees Tiger shine