我想問係different要加s定係same要加s！10分哦！

1. Different is an adjective, so you cannot add "s".
2. The noun form of different is = difference, this you can add "s" to make it into "differences".
3. Same is also an adjective, so you cannot add "s"

或者你想問的不是[different] 或[same]加[s], 是想問它們後面名詞[noun], 哪一個要加[s]...
different 是指不同, 當然牽涉到多於[一], 所以它後面的名詞理應是[眾/複數]
e.g. John and Mary are in different classes.
Different kinds of fish have different sizes.

same 是指相同, 同一, 所以它後面的名詞是用[單數]的, 不只這樣, 在same的前面要有[the]
e.g. John and Mary are in the same class.
Different kinds of fish may have the same size.