问题补充：
You will be successful in the interview you have confidence.
A. before
B. once
C. until
D. though
答案：
A. before
(答案→)B. once
C. until
D. though
解析：once的意思是“一旦”，又如：Once you have taken this decision, there will be no going back, ie you will not be able to change your mind. 一旦作出这个决定，你就不能改变主意。Once you understand this rule, you’ll have no further difficulty. 一旦明白了这条规则，就再也没有困难了。
