滑阀式伺服阀的阀芯台肩宽度小于阀体沉割槽的宽度,称为滑阀的()。
A.正开口
B.负开口
C.零开口
D.斜开口
参考答案:A
— David hasn’t come yet.
—I think he will ______ soon, for he means what he says.
A.turn on
B.turn off
C.turn down
D.turn up