1. according to是介词，其后原则上只接名词或代词，不接句子。若接句子，则要用according as。注意，according as后接的句子必须是没有任何“引导词”的句子。如：

Everyone contributes according as he is able. 每个人根据自己的能力作出贡献。

2. 对于那些由what, which, whether, how, when, where等引导的句子，其前要用according to，不用according as：

He is an honest businessman, according to what everyone says. 根据大家所说，他是位诚实的商人。

The amount of tax people pay varies according to where they live. 居住地不同，人们所交的税额也各不相同。

These apples have been graded according to how big they are. 这些苹果已经按照大小分了等级。

They were arranged according to when they happened. 它们是按发生的时间安排的。