—What do you think of your new job, Jim?
—It's _______. I do exactly the same thing every day.
A:confusing
B:misleading
C:interesting
D:boring
某舰艇以28海里/小时向东航行.在A处测得灯塔M在北偏东60°方向,半小时后到B处.又测得灯塔M在北偏东45°方向,此时灯塔与舰艇的距离MB是( )海里.