汇付方式是基于（）的结算方式。
A.国家信用
B.商业信用
C.公司信用
D.银行信用
参考答案：B
The Shanghai Expo has had a major impact upon China. It is the first World Expo _________ in a developing country in the event’s 159-year history.
A．having been held
B．to hold
C．being held
D．to be held
治疗原则为
A．抗休克
B．休克好转后手术
C．立即手术
D．抗休克同时手术
E．保守疗法
