–What is your sister going to be she grows up?
–She is going to be an engineer.
A. before
B. although
C. when
D. unless
网友回答
A. before
B. although
(答案→)C. when
D. unless
解析：A. before在…之前 B. although尽管 C. when 当…时候D. unless除非；句意：当你的妹妹长大后想要做什么？她打算做一名工程师。故选C