抗代谢药的抗癌机制是( )
A.影响核酸生物合成B.影响蛋白质合成C.直接破坏DNA并阻止其复制D.影响激素平衡E.干扰转录过程,阻止RNA合成
参考答案:A
These shoes look very good. I wonder _______.
A.how much cost they are
B.how much do they cost
C.how much they cost
D.how much are they cost
心肌上主要的肾上腺素受体是
A.β1 B.β2受体 C.M受体 D.N1受体 E.N2受体