On September 11,2001,intermational terroists hjjacked four commercial airplanes,two of which were used to destroy the twin towers of the world Trade Centerin New York City.
老师，这里的be used to不可以理解成过过去常常，应该是被动语态，被用于做某事，后面带to的不定式短语作状语吗？two ofused to／be used to／be used for有什么区别，这类是被动形式还是系表结构加状语形式？
On September 11,2001, intermational terrorists hjjacked four commercial airplanes, two of which were used to destroy the twin towers of the world Trade Centerin New York City.
【翻译】2001年9月11日，国际恐怖分子劫持了四架商用飞机，其中两架被用来摧毁纽约市世贸中心的双子塔。
【剖析】be used to do：指“主语被用来做某事”。此时，主语总是是表示“物”。
【一言辨异】be used to doing, be used to do, used to do:
The old man used to watch TV in the morning. Now he is used to taking a walk, and his stick is used to support him.
【翻译】这位老人过去常在早上看电视。目前他习惯了散步，他的拐杖用来支撑他。
