比较状语从句中的倒装The greater the number of the free electrons in a

你句子的完整表达是：
The greater the number of the free electrons is in a material, the better the conductivity of the material is .--------记住,第二个 is 应该在句末,你的原句的 is 的位置是错的.
为了方便你理解,我把你的句子变成非倒装句：
When / if the number of the free electrons is greater in a material, the conductivity of the material is better .
再简单点：
If / when she works harder, she will make more progress
------ The harder she works, the more progress she will make
(希望,你已经明白了.)