有个物质x是癌症的保护因素，还有个物质d跟癌症没关系，x和d组分相似，x不可测量，d可测量。 （1）进行队列研究，既摄入x又摄入d，结果会如何？ （2）再做个队列研究，只摄入d，结果会如何 把上面的文字翻译成英文流行病学题目

Title: Study on the protective factor of substance X for cancer and the similarity between X and substance D

Description: Substance X is a protective factor for cancer, and substance D is unrelated to cancer. X and D have similar components. X is not measurable, while D is measurable. Two queue studies were conducted to investigate the effects of intake of X and D on cancer incidence. The first study involved the intake of both X and D, while the second study only involved the intake of D.