I am not good at singing, so I can't sing so ________ as the other students.
A:more beautifully
B:beautifully
C:more beautiful
D:beautiful
若b<0,则二次函数y=x2+bx-1的图象的顶点在( )
下列关于核糖体的叙述,不正确的是
如图,在Rt△ABC的斜边BC上截取CD=CA,过点D作DE⊥BC,交AB于E,则下列结论一定正确的是( )