萤火虫用英语是：firefly。
firefly 英[?fa?fla?] 美[?fa?rfla?]
n. 萤火虫;
[例句]A firefly is a type of beetle.
萤火虫是一种甲虫。
In joy and sorrow, I will be my own firefly.
在喜悦和哀痛，我将是我自己的萤火虫。
A sympathetic firefly would have been enough for me.
如果有一只萤火虫同情地陪伴我，我就知足了。
This is actually the first time I have seen a firefly, so to me it felt amazing.
这实际上是我第一次看到萤火虫，所以觉得非常特别。
If you have ever seen a firefly then you have witnessed the same process in action.
如果你曾见过萤火虫，那么你其实就已经目睹了同样的运作原理。