The fire extinguisher is __the wall ___the back staircase
问题描述：
The fire extinguisher is __the wall ___the back staircase
第一个填in,第二个填at,为什么?特别是第一个,在墙上不应该是on吗?
答
因为灭火器是镶嵌在墙里的,所以用in .
如果是画picture则要用on.
at the back staircase.在楼梯间,既不是in也不是on,指标是其所在位置,用at+some place.
hope it is helpful for you.