Kate gets up late today ________ her clock doesn't work.
A:and
B:or
C:so
D:because
已知:①x+y=1;②x>y;③x+2y;④x2﹣y≥1;⑤x<0,其中属于不等式的有( )个.
方程x2+8x+9=0配方后,下列正确的是( )