适应高压或高压差、低噪音泄漏量小、调节性能好的调节阀是（）。
A、蝶阀
B、隔膜阀
C、偏心旋转阀
D、笼式阀
参考答案：D
Tom told us about the exciting news he knew all about it.[ ]
A. as well
B. as if
C. as usual
D. as for
磷化底漆不应直接刷于（）上.
A.金属面
B.色漆
C.清漆
D.防锈漆
E.红月
