星期五晚上是weekend还是weekday

星期五晚上是weekend还是weekday 是on weekday还是on the weekday是on the weekend 还是on weekend weekday 和weekend用on还是at weekday和weekend前面用in,on还是at weekday相当于 weekend相当于 weekday workday weekend 区别 on the weekday还是on weakday at还是in the weekend 还有以上的weekend w 是on weekdays还是on weekday? 是on the moring of weekday 还是 in the of weekday? 工作日是用weekday还是working day（workday）更好 weekend和weekday有什么区别 weekend & weekday 前面加什么介词?