中翻英：总有一天医生们能找到有效的方法治疗癌症。(when）

there will be a day when doctors find an effective cure for cancer

Doctors will finally find an effective way to cure the disease of cancer one day.

Doctors will find effective ways to cure cancers sooner or later.

The day will come sooner or later when docters figure out the cure for cancer.

it will be someday when the doctors find the methods to cure the cancer.

there is a day when cancer can be cured effectively by doctors