flint|flints

打火机需要更换燧石才能继续产生火花。

The lighter needs a new ___flint to keep making sparks.

他用燧石和钢片生火。

He started a fire by striking ___flints against a piece of steel.

尽管面临困境，他的意志如燧石般坚硬，从未屈服。

Despite the hardships, his will was as hard as ___flint, never yielding.