The same gestures, signs and so on, in other words, body language, may express different ideas or

meanings in different cultures, so don't use them _______ you are definitely sure of what they mean

so as to reduce misunderstanding ______ the smallest number.    [ ]

A. until; with    

B. unless; to    

C. until; by    

D. unless; by

进口押汇的适用币种限于：（）

A、美元

B、欧元

C、英镑

D、日元

E、港币