It was, in the words of my student, like touching a live wire.

用我的学生的话来说，的确就像触摸一根带电的电线。

When I was a freshman in high school, I was a live wire of nervous hormones.

当我是高一新生时， 我是一个神经激素异常活跃的人。

Charged particles guided by these magnetic fields can simply fly off the weak ends like sparks off a live wire.

带电粒子被这些磁场引导，能轻易飞出这个脆弱的边界（大气层），就像火花从电线那里飞出一样。

We talk about a " live wire" (live wire).

我们谈论的是“火线”（live wire）。

The man once was a live wire, but now he was listless because he was so busy with litigation.

这人曾是活跃的人，但现在他却无精打采因为他正忙于一场诉讼。