prep84 破折号的使用

ursula_1

The Nobel Prize in chemistry was awarded to three scientists for their discovery that plastic can be made electrically conductive--an advance that has led to improvements in film, television screens, and windows.

 

(A) that plastic can be made electrically conductive--an advance that has led

(B) that plastic can be made electrically conductive--this advance leading

(C) that plastic can be made to be electrically conductive, and this advance led

(D) of plastic's ability to be made electrically conductive, with this advance leading

(E) of plastic being able to be made electrically conductive--an advance that has led

B) this advance不符合同位语使用方法，
            应该用一个概括性名词结构，而不能使用特指。应将this改为an，变特指为概括性名词结构；

this advance leading to…缺少动词结构。
                这里我产生一个疑问，破折号究竟怎么用，是不是和分号一样，必须要求破折号后面句子成分完整呢？（如prep上所言）

请教大牛！

AlienX

emdash一般可以成comma...

ursula_1

谢谢版主