[求助]OG11-87

正确选项是

The energy source on Voyager 2 is not a nuclear reactor , in which atoms are actively broken apart, but rather a kind of nuclear battery that uses natural radioactive decay to produce power.

错误选项E是 apart , but that of 

对E的部分解释是【Rather should be included to emphasize contrast】

我明白E选项是错误的~~但是OG的这句解释让我很费解

not...but...和not...but rather...都是正确的短语to indicate contrast的啊~我觉得只是加了Rather以后更emphasize contrast ，更加好而已吧~不加rather怎么就错了呢？

请NN们指点指点咯~~ THANK U~~

啊~不对吧 呵呵

答案说了【that has no referent】not x but y 是个平行结构...所以but后的that不会是指代句首的The energy source，它顶多指代not 后的a nuclear reactor ...但是指代a nuclear reactor的话 but后就变成了but a nuclear reactor of a kind of nuclear battery了...很奇怪诶...所以that 不会是指代a nuclear reactor...所以OG说【that has no referent】

我是这样理解的啦~~^^