Mr Brown has been working in our school ___he came 2004 A.when B.before C.since 要理由的.
问题描述：
Mr Brown has been working in our school ___he came 2004 A.when B.before C.since 要理由的.
答
C
主句是现在完成时，需要一个时间段搭配，自从2004年以来，就是一个时间段，正好搭配。
祝你学习愉快！ (*^__^*)
请及时采纳，多谢！
答
C since 自从的意思