How the old people wish that they ____young once more为什么不能用could become而用were.But for water,it____impossible to live in the earth为什么用were 而不用would be

Question

How the old people wish that they ____young once more为什么不能用could become而用were.
But for water,it
____impossible to live in the earth为什么用were 而不用would be

Answer 1

were表示与现在事实相反的虚拟,所以用were 而could become表示与将来事实相反的虚拟.如
I wish I were rich now.
I wish I could fly to the moon someday in the future.
第一个句子中表示这些老人多么希望他们现在又年轻了.所以用表示与现在事实相反的虚拟.
第二句中的答案应该是would be也是表示若不是现在有水,我们生活在地球上是不可能的.也许你的答案有误.因为but for water=if there were no water.后面的应该是主句,所以要用would be 主句中的谓语时态没有用were的.