某新生儿出生后第3天，对其生命体征的描述，正确的是______

A．胸式呼吸为主
B．体温38.7℃
C．脉搏90次/分
D．心率100次/分
E．呼吸20～40次/分

I want to ring him _______ to know the reason why he rang _______ while I was speaking yesterday. [ ]

A. back;  up      

B. up;  off        

C. up;   down      

D. on;  off