介词on-in-under-的用法

SpeakEnglishPreposition视频播放oninunderon:在.......上面in:在......里面under:在......下面oninunderWhereistheeraser?Itis/It's___thebook.inWhereisthebook?Itis/It's___thetable.onWhereisthecat?Itis/It's_____theglass.under1.in表示在一定空间或范围里。2.on表示在表面或是平面上。3.under表示在下面，但一般是表示某物的正下方。Thebirdisthetree.Theappleisonthetree.Thecatisinthetree.Thedogisunderthetree.Thepeachisonthetree.Thepeachesareontheplant.Thegrapsareontheplant.1)门窗类一一镶嵌在墙上的，用in：字画一类一一挂在墙上的，用onHeputupamap____theblackwallbecausetherewasahole____itA:on,onB:inonC:oninThereisadoor____thewall.A:onB:inC:under2)鸟一类落在树上用的，用in,苹果一类长在树上的，用onTherearesomebirdssinging_____thetrees.A:onB:inC:underTherearemanyoranges_____thattreeA:inB:onC:under