For example, there are three balls of red, yellow and blue, and one person can only choose one. The three events of choosing red, yellow and blue are mutually exclusive and will not happen at the same time, but they are not antagonistic. Because you can choose blue or yellow instead of red.

When there are only two balls, red and yellow, and one person chooses, if only one ball can be selected, the two events of choosing red and choosing blue are opposite. Because it is either red or blue.