急需英语高手分析下下面句子结构特别是那几个which

Question

It’s a theory to which many economists subscribe, but in practice it often leaves railroads in the position of determining which companies will flourish and which will fail.

Answer 1

It’ s a theory （ 主句 ， 是主系表结构句子） to which many economists subscribe （定语从句, 修饰theory） but （ 转折连词，引导并列句） in practice （介词短语作 状语）it （ 主语） often （ 副词作状语） leaves （ 谓语） railroads （ 宾语）in the position of determining which companies will flourish and which will fail.（ 介词短语作宾语补足语 ）

to which many economists subscribe,是定语从句，修饰 theory ， to 是 和subscribe to 搭配的， 介词提到了关系代词which 之前， which 指代theory， 在句中作 subscribe to 的宾语。
which companies will flourish and which will fail. 是两个并列的宾语从句， 作 动词determining 的宾语，这两个which 都是 在 宾语从句中作定语， 修饰 companies， 第二个 which 后 省略了 companies 。追问

determining不是动名词么，which怎么引导宾语从句？

追答

不管是谓语动词还是非谓语动词，只要是及物动词后跟的从句就是宾语从句，如，Not knowing which way he should go,he asked the police for help.

Answer 2

It’s a theory ( to which ) [ many economists subscribe ],
这里的which指的是前面的theory,是一个定语从句, 那个to其实原本不是在那里的, 其实应该是和subscribe组成短语, subscriber to. 可以把它提去which前,大概如果句子长的话在末尾的介词会容易忘了.如果结尾是一个短语的话,其中的介词是可以提去which前的. 这句话的意思是:"这是一个许多经济学家都赞成的理论."

but in practice it often leaves railroads in the position of determining [ ( which companies ) will flourish and which will fail ].
这里的which和companies一起作主语.中括号内的是一个完整的句子.这个完整的句子作为determine的宾语,是宾语从句.你可以试试在which companies前面加上一个 that 来更加明显的表示出从句的存在,就会容易看出来很多,那个that被省略掉了. 这句话的意思是:"但是实际上它(指理论)经常使铁路部门处于决定哪些公司会兴旺哪些公司会衰败的境地."