to and fro vs. pro(s) and con(s)

to and fro vs. pro(s) and con(s)

辨析：两个短语的构成方式很类似。但前者形容“往复、来回”的运动，后者形容某件事物或某样举措“既有好处，也有坏处”。

例句：
The door swung to and fro and then stopped.
You know, there's pros and cons having him there, but that's what I have to do for myself.