. My parents live in a small village. They always keep candles in the house __________ there is a power cut.

A．if

B．unless

C．in case

D．so that

休克病人在哪种情况下，应及时应用血管收缩剂：（）

A.不能及时补充血容量

B.心功能不全时

C.全身给予抗生素防止肺内感染

D.血容量基本补足，循环状态仍未好转

E.尿量恢复后