门静脉高压症最危险的并发症是
A．肝性脑病B．血小板减少C．顽固性腹水D．充血性脾肿大E．食管、胃底曲张静脉破裂大出血
参考答案：E
如果每人节约1元钱，全国13亿人就节约______元钱；如果救助一个受灾家庭需要5000元，那么这些钱可以救助______万个受灾家庭．
All the guests at the party were dancing and singing happily _____ the electricity was cut off.
A．until
B．while
C．when
D．because
