1824年,法国科学家阿拉果完成了著名的“圆盘实验”.实验中将一铜圆盘水平放置,在其中心正上方用柔软细线悬挂一枚可以自由旋转的磁针,如图所示.实验中发现,当圆盘在磁针的磁场中绕过圆盘中心的竖直轴旋转时,磁针也随着一起转动起来,但略有滞后.下列说法正确的是( )
阅读。选择题,将正确答案的字母写在括号内。
I am Alice. We(我们) are in the playground(操场). We are playing football(踢足球). We are thirsty(口渴的). We are drinking. I like cola. Tom likes milk. Peter likes juice. Eddie likes water. We are happy.
29×63=____ 52×68=____ 89 ×40=____
356÷9= ____ 203÷4= ____ 903÷9=____
已知数列{an},a1=2,an+1= n+2n an,(n∈N*).