The boy__ on my left is our monitorA.seating B.seated C.sitting D.being sitting [ (B) why?]为什么不是The boy （who is） sitting on my left is our monitor 呢
问题描述：
The boy__ on my left is our monitor
A.seating B.seated C.sitting D.being sitting [ (B) why?]
为什么不是The boy （who is） sitting on my left is our monitor 呢
答
这个是个省略用法,完整的是The boy (who is) seated on my left is our monitor.