题目

如图，一艘海轮位于灯塔P的南偏东70°方向的M处，它以每小时40海里的速度向正北方向航行，2小时后到达位于灯塔P的北偏东40°的N处，则NP＝海里. 答案：【1】80The US Army suffered a record 32 suicides in July 2011, the most ______ it began publishing monthly figures in 2009.   [     ]A. since              B. when    C. while    D. though