Have you known Dr jackson for a long time?—Yes,since she()the chinese society
问题描述：
Have you known Dr jackson for a long time?—Yes,since she()the chinese society
A has joined B joins C had joined D joined 要解析
答
D.
since和时间点连用表时间段.joined过去式表示这一动作发生在过去某一时刻.
主句用完成时,也就是：
l have known Dr jackson since she joined the chinese society.题目没有提及时间点啊？时间点就是she joined the chinese society的时间呀完成时应该是had joined才是标准的完成时啊？我知道追问减慢了您的得分速度，所以又加了100分had joined是过去完成时；have/has done是现在完成时。这题用的是现在完成时。得分固然重要，把问题解释清楚，能够对你有帮助更重要!谢谢!