ppt的introduction可数吗

　　Our speaker today needs no introduction.

　　我们今天的发言人就不必介绍了。

　　It's a useful introduction to an extremely complex subject.

　　这是对一门极为复杂的学科的有益入门教程。

　　This album was my first introduction to modern jazz.

　　这张专辑唱片让我初次接触了现代爵士乐。

　　The introduction of a new tax accounted in no small measure for the downfall of the government.

　　这届政府的垮台在很大程度上归因于征收一种新税。

　　The introduction of a new code of criminal procedure has also slowed up the system.

　　新刑事诉讼法的出台也使系统的效率有所降低。