These are starfishes. The starfishes have five legs.

这些是海星，海星有五条腿。

"Excuse me, why are you throwing the starfishes back into the sea?" he asked.

“请问，你们为什么要把海星扔回大海呢？”他问。

Don't you think it is a waste of your time as there are hundreds of starfishes still lying around.

你们不觉得这是在浪费时间吗？还有成千上万只海星躺在岸上呢！

The man smiled and said, "It certainly would," so he too pick up the starfishes and threw them into the sea.

那人笑了笑说：“非常愿意。”于是，他也捡起海星，朝大海扔去。

He was surprised that a boy and a girl were not dancing but picking up the starfishes which were washed ashore by the tide and throwing them back into the sea.

他惊奇地发现，男孩和女孩并不是在跳舞，而是在捡被海潮冲上岸来的海星，然后把它们扔回大海。