It drinks juice from tree roots and it is covered in a hard shell.

它喝树根的汁液，并且有一层硬壳覆盖着。

youdao

This tree bears a hard red fruit.

这树结一种红色的坚果。

《新英汉大辞典》

Indeed, the tree was scored by innumerable gashes from the buffalo's horns. Mostly, however, the small herds are wary and hard to approach.

确实，这棵树上有很多水牛角刻出的无数的划痕。然而多数情况下，小兽群是很警觉的，一般不容易被接近。

youdao

Corals have hard, stony skeletons that grow like tree trunks.

VOA: special.2009.05.12

But our tree has been having a hard time recently -- this is our third one in as many years.

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