You could remove the mercury from some autistic children and not remove mercury from other autistic children and see if there was any difference in cognitive improvement over time.

• 你可以从某些孤独症的孩子体内移除汞，其他孤独症孩子体内的汞不被移除，看随着时间的过去孩子在认知改善方面有什么不同。