-Four dollars a pair? Ithink it's a bit too much.

-If you buy three pairs, the price for each will _______to three fifty.    [      ]

A. come down                  

B. take down    

C. turn over                  

D. go over

低血容量性休克代偿期，最先出现的代偿反应是（）.

A．脉压增大 

B．心率增快 

C．血压降低 

D．血压高 

E．心搏出量增加