laugh,laugher和laughing作名词时的区别?

laugh,laugher和laughing作名词时的区别? laugh和laugh at的区别 the South Pole和Antarctic作名词时的区别? permission 和permit 作名词时的区别 expense和expenditure作名词时的区别? reversal和reverse作名词时的区别 请问request和requirement同作名词时的区别. wish和will作名词时的区别 commitment(作名词时)和responsibility的区别? guard和guardian作名词时的区别 reply和response（作名词时）的区别? trust 和 confidence作名词时的区别