题目释义：Marconi conceived of the radio as a tool ….; instead, it has become ….

两个分句组成一个长句，前句主语Marconi，谓语conceive of sth as sth ，as a tool 作为宾语补足语，由定语从句进一步修饰；后句主语是it指代的radio,谓语为become的完成时态，宾语a tool。

考点

代词指代，固定搭配，逻辑表达

Opposite做名词时：a person or thing that is as different as possible from someone or something else

opposite of
What's the opposite of 'optimistic'?
She's quite shy, the exact opposite of Becky.
The two men were complete opposites - Simon tall and fair, Clive short and dark.
If anything, the opposite was true.
Is it sensible to think of masculine/feminine as polar opposites (=exactly or completely opposite) ?

1. conceive的固定搭配(cannot) conceive of (doing) something
   conceive that （不用虚拟语气）
   conceive of something/somebody as something
   conceive what/why/how etc
   conceive sth. (such as idea)
2. other than = With the exception of; except (for); besides:

选项分析

• A. Marconi's conception of the radio用法awkward，所有格套of结构；用conception名词，不够简洁。As多余；A tool应该修饰radio，但位置上却造成修饰telephone的歧义；It指代conception,逻辑意义荒谬。
• B. conceived of…as…用法正确；A tool应该修饰radio，但位置上却造成修饰telephone的歧义；But后的which不知道在修饰谁，前后都没有对应的部分，错；but前后不平行。
• C.正确。That跳跃修饰a tool(定语从句的引导词指代是可以根据逻辑跳跃不复杂的介宾短语)由于介词词组要紧跟其修饰对象，避免产生歧义，就把that从句放后面，如果把for private conversation换个地方，修饰对象改变后会产生逻辑错误；It指代radio?the ratio has become the opposite发展成了对立面；
• D. conceived of…to be…用法错误；which荒谬的修饰了telephone
• E. conceived of…to be…用法错误；A tool应该修饰radio，但位置上却造成修饰telephone的歧义。other than后面的句子，使得句意完全改变；other than=except，是"除了…以外"的意思，而且是介词短语，other than应改为rather than，且rather than可做介词亦可做连词，意思为"而不是…"；what it is中，it指代radio没有问题，用了一般现在时表示"现在radio成了什么"，逻辑上没错，但是使得句式复杂?the opposite说明其是做名词，是what的同位语，而后面再跟一个同位语a tool来修饰the opposite，实在太过复杂awkark。

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In B, ...as a substitute for the telephone, a tool for private conversation, but which..., i think "which" should modify "tool" or "conversation", am I right?

no.

that choice says "BUT which..." 
this means that "which..." is the second part of a parallel structure. the first part of this parallel structure is "a tool for private conversation".
BOTH parts of this parallel structure modify "telephone". (this is how parallel structures work: both/all parts of them MUST have the same grammatical function.)

题目释义：Marconi conceived of the radio as a tool ….; instead, it has become ….

两个分句组成一个长句，前句主语Marconi，谓语conceive of sth as sth ，as a tool 作为宾语补足语，由定语从句进一步修饰；后句主语是it指代的radio,谓语为become的完成时态，宾语a tool。

考点

代词指代，固定搭配，逻辑表达

Opposite做名词时：a person or thing that is as different as possible from someone or something else

opposite of
What's the opposite of 'optimistic'?
She's quite shy, the exact opposite of Becky.
The two men were complete opposites - Simon tall and fair, Clive short and dark.
If anything, the opposite was true.
Is it sensible to think of masculine/feminine as polar opposites (=exactly or completely opposite) ?

1. conceive的固定搭配(cannot) conceive of (doing) something
   conceive that （不用虚拟语气）
   conceive of something/somebody as something
   conceive what/why/how etc
   conceive sth. (such as idea)
2. other than = With the exception of; except (for); besides:

选项分析

• A. Marconi's conception of the radio用法awkward，所有格套of结构；用conception名词，不够简洁。As多余；A tool应该修饰radio，但位置上却造成修饰telephone的歧义；It指代conception,逻辑意义荒谬。
• B. conceived of…as…用法正确；A tool应该修饰radio，但位置上却造成修饰telephone的歧义；But后的which不知道在修饰谁，前后都没有对应的部分，错；but前后不平行。
• C.正确。That跳跃修饰a tool(定语从句的引导词指代是可以根据逻辑跳跃不复杂的介宾短语)由于介词词组要紧跟其修饰对象，避免产生歧义，就把that从句放后面，如果把for private conversation换个地方，修饰对象改变后会产生逻辑错误；It指代radio?the ratio has become the opposite发展成了对立面；
• D. conceived of…to be…用法错误；which荒谬的修饰了telephone
• E. conceived of…to be…用法错误；A tool应该修饰radio，但位置上却造成修饰telephone的歧义。other than后面的句子，使得句意完全改变；other than=except，是"除了…以外"的意思，而且是介词短语，other than应改为rather than，且rather than可做介词亦可做连词，意思为"而不是…"；what it is中，it指代radio没有问题，用了一般现在时表示"现在radio成了什么"，逻辑上没错，但是使得句式复杂?the opposite说明其是做名词，是what的同位语，而后面再跟一个同位语a tool来修饰the opposite，实在太过复杂awkark。

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Per OG explainations, in both B and D "which" modifies telephone, which really confuses me. 

In B, ...as a substitute for the telephone, a tool for private conversation, but which..., i think "which" should modify "tool" or "conversation", am I right?

no.

that choice says "BUT which..." 
this means that "which..." is the second part of a parallel structure. the first part of this parallel structure is "a tool for private conversation".
BOTH parts of this parallel structure modify "telephone". (this is how parallel structures work: both/all parts of them MUST have the same grammatical function.)

In D, ...be a tool for private conversation, a substitute for the telephone, which... i think "which" should modify "sbustitute" or "telephone", am I right?

no, at least not based on what we've actually seen.

WARNING: THE FOLLOWING EXPLANATION IS BASED ONLY ON WHAT WE HAVE SEEN IN OFFICIAL PROBLEMS.

from what we've seen - if you have "which" following "noun1 + preposition + noun2", then "which" can refer to noun1 only if noun2 is grammatically ineligible. otherwise it automatically refers to noun2.