An adjunct professor is hired to teach for a limited time, usually one semester.

VOA: special.2009.04.09

That is a course that I like to teach, too; usually I teach Plato to T.S. Eliot or Plato to I.A. Richards or some other important figure in the early twentieth century.

这也是我喜欢教的一门课;,我通常教从柏拉图到T。S。艾略特,或从柏拉图到T。A。理查兹,或者其他20世纪初的重要人物。

耶鲁公开课 - 文学理论导论课程节选