according as，according to

这两个词组虽然相似，但它们的结构和使用场合并不相同。according to表示"根据"、"按照"；而according as表示"视乎"，有depending及according to whether的意味。

According as是连词词组，其后接从句；according to 是介词短语，其后接名词。例：

The thermometer rises or falls according to the high or low temperature．
寒暑表根据气温的高低而升降。
They will be praised or blamed according as their work is good or bad．
给他们的赏罚将视乎他们工作的好坏来决定。

应当在此指出，在现代英语中，according as的句型结构已很少有人使用，正如 Bergen Evans和 Cornelia Evans在A Dictionary of Contemporary American Usage 中指出的那样："This construction is not often heard today"。
下面是according to的例句：
According to the weather report，we shall have cold weather next week．
根据天气报告，下星期天气将要转冷。
You should act according to circumstances．你们要随机应变。

According to有个同义短语，即 in accordance with，但它们的涵义有细微的区别，前者强调"根据…所言"，后者则强调"与…要一致"。另外 in accordance with多用于正式场合，例如表示与一些原则、规律一致。例：

According to police report，five luxury cars were stolen in Kowloon yesterday．
根据警方报告，昨天在九龙有五辆豪华汽车失窃。
We must proceed in accordance with the rules．
我们必须按照规章办事。
That sentence is not in accordance with the rules of grammar．
那个句子不符合语法规则。

请注意，in accordance with 既可引导 adverbial phrase，又可引导adjectival phrase作verb"to be"的补语（见上面 in accordance with的第一和第二个例句）；according to则不能。例如，我们不能说：
The news is according to Hong Kong's broadcasting station．（错）

另一点需要补充说明的是，in accord with 和 in accordance with同义，它们可以互换使用，但前者远不及后者用得普遍。英国学者F．T．Wood认为，我们最好在强凋"与…一致"（agreement）的时候，用in accord with；在强调"服从"或"遵照执行"（obeying or following）的涵义时，用 in accordance with。例如：

What he has done is not in accord with your instructions．
In accordance with your instructions we have suspended work on the heating apparatus．