应该是is前面是可数名词单数和不可数名词。are前面是可数复数。is 与are对应前面的主语，跟后面的宾语没有关系。

相关介绍

Patience is one of the most important attributes in a teacher.

耐心是教师最重要的品质之一。

A single red LED shows that the power is switched on.

单支红色发光二极管表示电源已接通。

No new SARS cases have been reported in the region.

该区没有新增非典型肺炎病例。

A number of measures were taken to alleviate the problem.

采取了一系列措施缓解这个问题。