They serve the purpose of changing hydrogen into breathable oxygen.
它们的目的是为了把氢气转化为可供呼吸的氧气

And they're as necessary here as the air is, on Earth.
它们在这里的重要性如同地球上的空气一般。

But I still say, they're flowers.
但我想说的是，它们是花，仅此而已。

If you like...
随你怎么想吧。

Do you sell them?
你卖这些花吗？

I'm afraid not.
我想我恐怕不卖它们。

But, maybe we could make a deal.
但也许，我们可以做个交易。

What do you mean?
你的意思是?