/q-25015.html
Then Wang Ping flashed a switch on a computer screen, and a table and some chairs rose from under the floor as if by magic. ——请问：这句话from后面为何还有一个介词under? 只用一个可以吗？
▲ 我们知道from 是个介词，为什么之后还有一个介词 under，两个介词不是重叠了吗？感觉好像在from之后省略了什么，但总是讲不出来。这是怎么回事？
从句义上看，两个介词一个都不能少，如果删去任何一个，句子的意思都不完整：
（1）A table and some chairs rose from the floor as if by magic.（rose from the floor 是从地板的上面还是下面，我们无从判断。）
（2）A table and some chairs rose under the floor as if by magic.（rose under the floor 在地板下面升起来，不知所云）
那么，from under the floor 究竟包含什么意义呢？经过分析我们发现，在from和under之间确实省略了一个词somewhere（某个地方）。也就是说，上面的英语句子可以理解为“一张桌子和几把椅子像魔术般地从地板下面的某个地方升了出来。”
下面再举一些常见的例子：
The thief came from behind the door and searched the room for something precious. 小偷从门后出来，搜索房间寻找有价值的东西。（我们不能说：The thief came from the door. 也不能说：The thief came behind the door. 省去任何一个介词，句子都讲不通！）
The stranger is difficult to recognize from among the crowd. 那个陌生人很难从人群中辨认出来。
She picked up several bigger eggs from within the box. 她从箱子里面挑选了几个较大的鸡蛋。
A red flag rose up from before the building. 一面红旗从大楼前升了起来。
Sounds came from below our feet as we rose slowly from the ground. 当我们从地面上慢慢升起的时候，从我们脚下传来（嗡嗡的）声音。
That is a force pushing outwards from inside the moon. 那是一种从月球内向外推的力。
The National Games attracted many athletes and reporters from throughout the country. 本届全运会吸引了来自全国各地的运动员和记者。
Thanksgiving Day in the U.S.A., like Spring Festival inChina, brings families back together from across the country. 像中国春节一样, 美国的感恩节是家人从全国各地团聚在一起的节日。
The monkey suddenly emerged from behind the tree, frightening Lucy into screaming. 猴子突然从树后出现,露茜吓得尖叫起来。
That he was determined to study medicine dated from before the war. 他立志学医始于战前。
She’s lived there since before the war. 她从战前起就一直住在那里。
Can you take me there for under ten dollars? 10美元以下你能送我去那里吗?
Mom said that she would not allow me to buy a new computer unless the price dropped to below 2000 yuan. 妈妈说除非计算机降到2000元以下，否则就不允许我买。
In between the chores, Jim managed to spend 50-60 hours a week working at the computer or doing reporting for the freelance articles he sells to magazines. 趁做家务活的闲暇时间里，吉姆每周抽出50至60小时做一些电脑工作，或者以自由记者的身份写一些报道,投给杂志社。
I am free except after lunch. 除了午饭后外，我其他时间都有空。
= except the time after lunch
The buses run until after twelve. 公共汽车一直行驶到午夜以后。
18.The German team were winning the match until just before the end when the other team equalized. 德国队眼看要赢得这场比赛, 而恰在终场前对方把比分扳平。
The disco went on until beyond midnight. 迪斯科舞会一直持续到午夜以后。
从上面句子中，我们发现双重介词的正确使用，不仅能帮助我们准确地理解原文，而且还会让人觉得句子表达言简意赅。
In Paris President Emmanuel Macron made a lengthy speech calling for an ambitious new programme of European integration that he said would take until 2024 to complete. 在巴黎，马克龙总统发表了一份长篇演讲，呼吁建立一个宏伟的欧洲一体化计划，他说，（该计划）要到2024年才能完成。
take 是“花费”之意，宾语是until 2024，这是省略说法，相当于从现在到2024年这段时间。take until 2024 = take the time from now until 2024
