on,over,above
on表示在一物体上,强调两物相接触,over也表示在一物体上,但强调覆盖这一物体.
试比较：① She put her coat on the bed.她把大衣放在床上.
② She put her coat over the sleeping baby.她把大衣盖在那正在睡觉的孩子身上.
③There’s a magazine lying open on the table.桌上有本杂志翻开着.
④There’s a cloth over the table.桌上摊着一块台布.
⑤ The woman lifted a big jar on her head.那位妇女头上顶着一只大坛子.
⑥ She put her hands over her face.她用手遮住脸.
over表示“越过”某一高度,具有动态之意,on仅表示“处于„„之上”,是静态.
试比较：⑦ They dragged heavy stones with ropes over their shoulders.他们肩背绳索拖拽巨石.(绳在肩膀两边弯下去,不用on.)
⑧ To my horror,I saw,over my father’s shoulder,a gorilla,the worst enemy of the soldier in Africa.使我感到恐怖的是,从我父亲的肩膀上看过去,我发现非洲士兵最危险的敌人--------一只大猩猩.(视线越过肩膀后,一直向前方延伸,不用on.)
⑨ The farmers walked to their fields with hoes on their shoulders.农民们肩上扛着锄头,向田地走去.(仅表示锄头所处的位置.是静态,用on,不用over.)
over和above都可以用来表示“高于”,相当于“higher than”.
例如：① The water came up over/above our knees.水已涨至我们膝盖之上.
② Can you see the birds flying above/over the pear trees?你看到那一片梨树上空飞翔的鸟吗?
▲如果要表示“覆盖”或“越过”,则用 over.
如：③ There’s thick cloud over the south of England.英格兰南部地区一片乌云.
④ Electricity cables went over the fields.电缆线越过田野.(这句也可以用across)
▲指数量时,我们一般用 over(＝more than)表示“超过”,但如果指上下 垂直的度量以及海拔高度时,要用 above.试比较：
⑤ You have to be over 18 to see this film.你得超过十八岁才能看这部电影.(不用above)
⑥ The temperature is three degrees above zero.温度在零上三度.(不用over)
⑦ The mountain is over(＝more than)4,000 metres above (higher than) sealevel.那座山海拔有四千多米高.
▲ over表示在某人或某物的正上方,反义词是under.
above表示位置高于某人或某物.但不一定是正上方,反义词是below
