looker-on

基本解释

Right! For example, often because I had done a plan, I was very excited. But she was a looker-on and corrected my plan, having her correction, the plan would be completed.
对，比如说我做的方案经常是因为刚做完，非常激动，她就会用一个很旁观的眼光和态度来对我的方案作出纠正，所以有了她的修正，这个方案就会完整很多。
blog.sina.com.cn
THERE is a looker-on who sits behind my eyes. It seems he has seen things in ages and worlds beyond memory's shore, and those forgotten sights glisten on the grass and shiver on the leaves.
我的双眸背后，有一个旁观者，他仿佛见过远古时代的事物，熟悉混沌初开时的世间生活，而这些被人遗忘的情景在草茎上闪烁，在树叶上颤动。
There is a looker-on who sits behind my eyes.
有一个旁观者，坐在我的眼睛后面。

someone who watches something that is happening in a public place but is not involved in it