New computers are soon out of date since newer models are ________ constantly.

A．turned up

B．turned out

C．turned down

D．turned over

干扰转录过程和阻止RNA合成的药物是（）

A.柔红霉素

B.环磷酰胺

C.阿糖胞苷

D.紫杉醇

E.雌激素