weekdays 前面用 on 还是用 in 还是用 at

weekdays 前面用 on 还是用 in 还是用 at weekdays的前面究竟是用介词on还是at,急! on weekdays还是at weekdays He usually goes to school on weekdays(on weekdays用tomorrow改写此句)怎么写 后天期末on weekdays 还是in weekdays?in the weekends 是on weekdays还是on weekday? my friend jack works hard in a factory on weekdays.为什么用weekdays而不用weekday holiday前面用on还是用in 年份前面是用on还是in? China前面用in on 还是at many ways前面用in还是on Saturday afternoon前面用on还是in home前面用介词on还是in? December前面用in还是on sunday前面用介词in还是 on January.1699前面用in,还是on studens-----cshool uniforms on weekdays,but on weekends they.can--more casually.为什么用wear;dress? The bank closes 《at 7：30》 on weekdays 用whenThe bank closes 《at 7：30》 on weekdays 用when提问 急