下列因式分解正确的是( )
A:x3﹣x=x(x2﹣1)
B:x2+3x+2=x(x+3)+2
C:x2﹣y2=(x﹣y)2
D:x2+2x+1=(x+1)2
青藏地区的主要作物有____
7+8=____
—I'm not good at basketball,you know.
—________.We are playing for fun. Just try and you'll see you can.( )