同学你好，该知识点来自沪江网校《英语零基础直达大学六级【全额奖学金班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~

While he was busy measuring the wall, a policeman went over and asked him what he was doing.
went over可以改成came towards him

Though the journalist explained that he was a reporter and his editor had asked him to find out the exact number of steps and height of the wall, the policeman refused to believe him.
steps前可以加the特指

He was arrested and sent to prison because the police thought that he might a spy from other country.
might后面加be，也许是
other country可以改成another country另一个国家，another表示同类中的另一个

This proved to the police that the man certainly was guilty and deserved to stay in prison.
certainly 可以去掉，改成the man was indeed guilty 这个人确实有罪

祝同学学习进步~