They were in time to produce carbon,.,which were to make the earth's atmosphere.
问题描述：
They were in time to produce carbon,.,which were to make the earth's atmosphere.
which 后面的were to make是be to do 是表示将要,
答
这和那个关联不是重点,这里的were to do 只是对which 指代的句子作谓语来解释说明,可以做目的来理解,“它们及时的产生CO2,来组成地球的大气.”