A:帮助果树消灭害虫
B:刺激子房快速发育
C:延长花的开放时间
D:帮助果树进行传粉
To be an artist is not easy, but sometimes dreams can be a rich source of ________—for an artist.
如图,边长为1的正方形ABCD绕点A逆时针旋转45°后得到正方形AB1C1D1,边B1C1与CD交于点O,则四边形AB1OD 的周长是( )
- How many socks are there in eleven pairs? ( )
- _______
8的平方根是( )