at table 在用饭；吃饭时
　at the table 在桌旁
　He seldom talks at table.
　They sat at the table, talking and laughing.

    by day 白天；日间
　by the day 按日计
　He works in an office by day.
　Cleaning women in big cities get paid by the day.

    take place 发生；举行
　take the place 代替；接替
　When did this conversation take place?
　Electric train has now taken the place of steam trains in England.

    in words 用言语
　in a word 总之
　Please express your thought in words.
　In a word, I don't trust you.

    at times 有时；不时
　at a time 一次
　I do feel a little nervous at times.
　Pass me the bricks two at a time.

    little 少；不多的
　a little 一些；一点点
　Hurry up, there's little time left.
　Don't hurry, you still have a little time.

    few 很少；几乎没有的
　a few 有些；几个
　He is a man of few words.
　Only a few of the children can read.

    a most interesting 非常有趣的
　the most interesting 最有趣的（形容词的最高级）
　This is a most interesting story.
　This is the most interesting story of the three.

    a doctor and nurse 一位医生兼护士
　a doctor and a nurse 一位医生和一位护士
　A doctor and nurse is standing there.
　A doctor and a nurse are standing there.

    A number of 许多；好些
　the number of …（的）数目
　A number of students are in the classroom.
　The number of students in the classroom is forty.