Micro-expression refers to people expressing their inner feelings to each other by making some expressions. Between different expressions that people make, or in a certain expression, the micro-expression will leak other information. The shortest micro-expression can last 1 /25 seconds, although a subconscious expression may only last for a moment, it is easy to expose emotions. When the face is doing a certain expression, these very short-duration expressions will suddenly flash by, and sometimes express the opposite mood.
According to the above definition, which of the followings is a micro-expression?
Spies send messages to their accomplices through the blink of an eye