方式从句

　　主要由 just as, as, as if, as though 等连词引导，如：
　　　　He doesn't speak the way as other people do.
　　　　Our bodies are made up of millions of very small cells, just as a building is made of many stones or bricks.
　　　　He speaks French as if (as though) he were a Frenchman.

　　由 as if 或 as though 引导的从句通常用虚拟语气，但如果主句谓语是感官动词，并且所述情况实现可能性大，也可用陈述语气，如：
　　It looks as if the coming autumn harvest will be even better than the last one.

　　比较从句

　　主要由 as ... as, not so (as) ... as, than 等连词引导，如：
　　　　This table is as wide as that one.
　　　　Mary can not run so (as) fast as Tom.
　　　　Silver conducts electricity better than other metals.