英语成语、短语、惯用语很多。有时，它们的构造看起来不合逻辑，甚至不合常理，但又不能随意更改。例如，我们用双脚步行，应该是“on feet”，但偏偏是“on foot”才对。一般上说，成语、短语或惯用语中的字眼不可用别的字取代，词序也不可调换，因为一字之差，词序一换，原意可能走样，甚至毫无意思。
　　在下列各组句子中，(a)错、(b)对：
　　1a. What is the reason of all this shunning away from blue-collar work?
　　b. What is the reason of all this shying away from blue-collar work?
　　2a. I am working on the behalf of my company.
　　b. I am working on behalf of my company.
　　3a. We need a capable person to help us in time of difficulties.
　　b. We need a capable person to help us in times of difficultes.
　　4a. In term of economic development, our country has done a good job.
　　b. In terms of economic development, our country has done a good job.
　　5a. Few would like to make friend with hypocrites.
　　b. Few would like to make friends with hypocrites.
　　6a. Let‘s discuss this matter in details.
　　b. Let‘s discuss this matter in detail.
　　7a. That rich woman is covered with jewellery from top to toes.
　　b. That rich woman is covered with jewellery from top to toe.
　　8a. For the better or worse, we must try to get along with our colleagues.
　　b. For better or worse, we must try to get along with our colleagues.
　　9a. The Public Relations Officer did not speak much. What is worst, she hated to mingle with people.
　　b. The Public Relations Officer did not speak much. What is worse, she hated to mingle with people.
　　10a. All must come to the meeting without failure.
　　b. All must come to the meeting without fail.
　　11a. Most of the students learn historical facts by hard.
　　b. Most of the students learn historical facts by heart.
　　12a. A holiday abroad will take your mind of the work tension for a while.
　　b. A holiday abroad will take your mind off the work tension for a while.
　　13a. It is out of question for you to go tonight; you haven‘t finished your assignment yet.
　　b. It is out of the question for you to go tonight; you haven‘t finished your assignment yet.
　　14a. Students should spend their time studying instead of involving in destructive activities.
　　b. Students should spend their time studying instead of involving themselves in/ getting involved in destructive activities.