【单选题】At weekends we help mother with housework in the kitchen _____ she can enjoy herself by searching the Internet. [ ]
【判断题】变量数列编制中,在条件不变的情况下,组数分得越多组距也就越大。
【判断题】变量数列编制中,在条件不变的情况下,组数越多,组距越大。( )
【简答题】( )是指国家利益不受威胁、侵害和破坏的客观状态。
【单选题】We don’t go to school _____ weekends. [ ]
【单选题】Mother was always a bit __________ if we failed to arrive home on time especially on weekends.
【单选题】We often go shopping _________ weekends. [ ]