重头戏

重头戏:

Literally means:

an important opera play; important part of something

Actually means:

It literally refers to an opera in which both singing and acting are significant. It figuratively refers to the most important part of something or an activity. It may also refers to a person who plays an important role.

指唱（唱歌）和做（动作和表情）两方面都很重要的戏曲。比喻某件事情或某项活动中最重要的部分，或在其中起重要作用的人物。