Do you remember all those years when scientists argued that smoking would kill us but the doubters insisted that we didn't know for sure?
这句话并不缺成分,为什么when引导的是定语从句而不是时间状语从句?
这里的 when引导的是定语从句。如果作为时间状语从句,译为汉语句子就不合乎逻辑。