外汇期货交易有哪些基本原则？
参考答案：
（1）保证金制度。
（2）每日结算制度。
（3）现金交割。
— Have you ever been to France?
— Yes, I ______ there last August. [ ]
A. have gone
B. went
C. have been
D. were
游客游览景区时发生流行性感冒该如何应对？
