on alternate weekends 是什么意思?用英语怎么解释?谢谢!请用简单英语翻译一下,谢谢.

alternate alternate alternate on my next weekend on the weekend or at the weekend 如何区分at weekend 与 on weekend Alternate是什么意思 alternate是什么意思 Alternate Email alternate state 我们说 on weekend ,at weekend,还是in the weekend 英语翻译There are clearly identifiable streams of research that rely on alternate models of defining on alternate weekends 是什么意思?用英语怎么解释?谢谢!请用简单英语翻译一下,谢谢. 一下短语有什么用法区别?At weekend.On weekend.At the weekend.On the weekend. () the weekend in or on? this weekend前要加on么 关于on weekend和on the weekend的问题是on weekend还是on the weekend,还是两者都可以? on weekend什么时候用s?