第十三单元
1.常考单词：
compel voluntary undertake coincide manual efficiency compulsion division eliminate boring amusement so far as …knows to coincide with attitude toward to go in for
2. 常考句子：
1） he cannot be really happy if h is compelled by society to do what he does not enjoy doing.
2） whether a job is to be classified as labor or work depends，not on the job itself，but on the tastes of the individual who undertake it.
3） the difference does not，for example，coincide with the difference between a manual and a mental job.
4） so that it is natural for him to imagine that the fewer hours he has to spend laboring，and the more hours he is free to play，the better.