So by comparing how similar GCSE results are in identical twins versus non-identical twins, and doing some clever math, we can an idea of how much variation and performance is due to the environment and how much is due to genes.
因此，通过比较同卵双胞胎 与异卵双胞胎的 GCSE的成绩， 做一些巧妙的计算后， 我们就可以知道有多少 表现和差异来自环境， 有多少是受基因的影响。