是Look,there are some books on he bookcase还是Look,there are so

in the bookcase.
书架是有空间的.要用IN.
再问： Look,there are some toys on the bookcase还是Look,there are some books on the bookcase
再答： 这个要根据语境了。 On the bookcase是在书架的顶上面 in the bookcase是 在书架上（就是书架里面）
再问： 那这个呢，玩具就在书架上面
再答： Look,there are some toys on the bookcase.可以用。