A:4
B:16
C:5
D:25
已知数列{an}的前n项和为Sn,满足Sn+1=2Sn+2n+1(n∈N*),且a1=1.
(Ⅰ)求证{an+2}是等比数列;
(Ⅱ)求Sn.
用牛顿第三定律判断下列说法正确的是( )
My grandma's birthday is on October sixth. (对画线部分提问)
____ ____your grandma's birthday?