问题
选择题
Before joining the Department of Defense, Mr． Panetta _______ as director of the CIA from February 2009 to June 2011．
A．would serve
B．served
C．was served
D．had been served
答案
答案：B
考查时态。根据本句的时间状语：from February 2009 to June 2011说明在过去的时间发生的事情，使用过去时即可。Serve没有被动语态。故B正确。