分析几句英语（求高手）some kinds of substances are better for certain purposes than are other kinds of matter.疑问：第二个are是怎么回事,怎么这么用啊He smoked more cigarettes than are good for him.疑问：这个句子结

分析几句英语（求高手）some kinds of substances are better for certain purposes than are other kinds of matter.疑问：第二个are是怎么回事,怎么这么用啊He smoked more cigarettes than are good for him.疑问：这个句子结
分析几句英语（求高手）
some kinds of substances are better for certain purposes than are other kinds of matter.
疑问：第二个are是怎么回事,怎么这么用啊
He smoked more cigarettes than are good for him.
疑问：这个句子结构是什么,读起来好别扭
my typewriter is not the machine ___ it was.
than/ as/ that/ which 填哪个,是什么用法

分析几句英语（求高手）some kinds of substances are better for certain purposes than are other kinds of matter.疑问：第二个are是怎么回事,怎么这么用啊He smoked more cigarettes than are good for him.疑问：这个句子结
1.我觉得第一个are应该是用了倒装,原句可能是some kinds of substances are better for certain purposes than other kinds of matter are（后面省略了better for certain substances,而后面省略的部分比较长,故用倒装,句子看起来前后比较平衡）
2.more··· than··· 的结构这个很常见啊,经常读一些书的话有语感就不会奇怪了
这个句子要拆开来理解,he smoked more cigarettes ,than (that )are good for him他抽烟过多,对身体不好
3.当关系代词在定语从句中作表语是,只能用that,也可以省去,不能用which,因此此处应该用that