我踩到了一块板子上突出的钉子。

I stepped on a ___nail sticking out of a board.

在墙上钉一个钉子，我们好挂镜子。

Hammer a ___nail into the wall and we'll hang the mirror on it.

有时在游客给动物的食物中，你会发现玻璃片、钉子甚至毒药。

Sometimes in food given to animals by visitors you can find pieces of glass, ___nails or even poison.