1. It suddenly occurred to one of the workers to open up the box.
突然一个工人想到打开箱子看看。
知识点1：sth. occur to sb. to do sth. 某人想到做某事
知识点2：it为形式主语，真正的主语是不定式to open up the box
2. He was astonished at what he found.
看到的情景使他吃惊。
知识点：what he found作at的宾语，此处的what相当于the thing that。
3. He was so surprised at being discovered that he did not even try to run away.
他由于被人发现而感到非常吃惊，甚至都没有企图逃跑。
知识点1：本句包含so...that结构，其中动名词短语being discovered作介词at的宾语。注意：being discovered是被动语态的形式。
知识点2：本句中的主语“He”并非打开箱子的工人，而是被关在箱子里的那个人，本句主语交待得不够清楚，需根据上下文判断。
4. He had had a long and uncomfortable trip, for he had been confined to the wooden box for over eighteen hours.
他经历了一个既漫长而又难受的旅程，因为他在木箱里闷了18个多小时，
知识点：本句中for引导原因状语从句。主句使用过去完成时主动语态，从句中使用过去完成时的被动语态。
