look up的用法如下:
look up 是动词加副词的结构,意思是查找。常见短语是look sb up,look sth up.
例句:She looked up and saw me.
她抬头看见了我。
抬起头看某人:look up at sb. at不能少.look up sth :查找某物,查阅.但可以说look sb up(久别后)拜访某人.
抬起瞎嫌头看某人或某物 look up at sb/sth.低头看某人或某物 look down at sb/sth.
look up to sb.尊敬某人. look down on/upon sb 瞧不起某人.
当指向上看的时候,look up 作为一个整体,加上at后才能接所看的人或物,而当指查阅时,up后直接跟物.可孙扒以这样理解,look up at sb 中的up 为副词,意为"向上则神昌",修饰look,所以后要接名词的话,需加上介词at, 而look up sth中的up 就为介词,直接加物.