关于平行结构

rorochen

When the technique known as gene-splicing was invented in the early 1970's, it was feared that scien­tists might inadvertently create an "Andromeda strain," a microbe never before seen on Earth that might escape from the laboratory and it would kill vast numbers of humans who would have no natural defenses against it.
        

分析下句子： When从句 +  主句 it was feared that ......  an "Andromeda strain' +  同位语 a microbe + that 定语从句 

When the technique 从主 (known as gene-splicing) 修饰technique  was invented  从谓 （in the early 1970's ）,  [it was feared that scientists might inadvertently create  an "Andromeda strain" ]  主句  , a microbe  (做 an Andromeda strain同位语) <never before seen on Earth> 修饰 microbe [ that might escape from the laboratory and it would kill vast numbers of humans who would have no natural defenses against it. ] 这一串是that 引导的定语从句，修饰a microbe， that直代 a microbe， 在丛句中作主语， 然后，

incorrect:  might escape from the laboratory and it would kill vast numbers of humans who would have no natural defenses against it.

如果用it, 就打破平行了

correct : might escape from the laboratory and kill vast numbers of humans who would have no natural defenses against it （it 指代 a microbe，所以单数，不是them）

and 并列结构前后平行

(A) it would kill vast numbers of humans who would have no natural defenses against it

(B)
     it might kill vast numbers of humans with no natural defenses against it

(C) kill vast numbers of humans who would have no natural defenses against it  （正确）

(D) kill vast numbers of humans who have no natu­ral defenses against them

(E) kill vast numbers of humans with no natural
    defenses against them

以上是仅代表个人想法，如果有问题，大家要严厉指出阿~~~ 谢谢~~