它看起来很像天然形成的。

It looks ___natural.

这些岩石是由自然力量形成的，不是人工雕刻的。

These rocks were shaped by ___natural forces, not carved by humans.

考试前感到紧张是很正常的。

It's ___natural to feel anxious before an exam.

他在篮球场上是个天生的好手。

He's a ___natural on the basketball court.