第6题: [单项选择]By the time she takes the entrance examination, Louis ______ Spanish for five years. A. had been studying B. has studied C. will have been studying D. will study 参考答案:C 答案解析:一般说来,如果以by the time引导的从句使用的是现在时,那么主句是用将来完成时。又因为主句出现了表示持续时间的短语for five years,因此,本题的主句应该用将来完成进行时。