单项选择题采用事先防范原理之前我们必须承认一个事实,即,没有任何系统是完美无缺的。
单项选择题What does the author mean by saying ' these ' temporary' jobs have a habit of becoming permanent' ?A.Once college graduates take a temporary job, they soon become used to it.B.College graduates have developed the habit of taking temporary jobs.C.Many college graduates might never find jobs for which they were traineD.D.More and more college graduates are unwilling to change their jobs.