调压阀内的节流针阀的作用是()

(A)截断和导通流体;

(B)调节流量;

(C)控制气流压力;

(D)控制作用与调节阀膜头上的压差

At last we came to a mountain, at the top of which ______,

A．a temple stood

B．is there a temple

C．stood a temple

D．there is a temple