引起传染病的是( )
A:病原体
B:组织损伤
C:细胞病变
D:遗传
判断对错.
圆的半径越长圆就越大.
在△ABC中,角A,B,C所对的边分别为a,b,c,若b3cosB=asinA,则cosB=( )
已知正四棱锥S-ABCD的侧棱长与底面边长都相等,E是SB的中点,则AE,SD所成的角的余弦值为( )
— What does that man look like?
— He's of medium height and very ____.