翻译：It is just an act.
It is just an action
It is only an act. "only" and "just" are the same meanings here.
It is just an act听起来像是“这只是一幕”，movement（甚至口语中move）或者action比act要好。
it is only an act .
act as a noun is more like a pretense or a show, a play
只是 is just