this road is four times longer than that one等于 this road is

this road is four times longer than that one等于 this road is five times as long as that one .,请具体讲清楚点 ,.
还有 这种句型的 as ..as 中间加 形容词和副词对吧 .
We got three times as many people as we expected .中间 many people 怎么讲 .
还有个小疑问,his earnings were only half the amount they used to be .后面的they used to be 是个定语从句 ,我怎么也想不明白 ,如果他的完全形式是什么 ,难道翻译起来是 他过去是.

这条路是那条路的四倍长,这条路是那条路的五倍长,as……as…就是跟…一样……的意思.
这里的many people当人数讲.加that看看,翻译成他们过去赚得.his earnings were only half the amount that they used to earn.