Question

主语从句的时态

Answer 1

S主语：主语是执行句子行为或动作的主体，是必要句子元素。

V动词：表示动作中状态的词叫做动词。

O宾语：宾语表示动作所涉及的对象。它通常是一个名词词组或者相当于名词词组的结构。宾语可分为直接宾语、间接宾语、同源宾语等。

P表语：表语是回答主语“是什么”或“怎么样”的语法成分。它修饰的是主语，表语是用来说明主语的身份、性质、品性、特征和状态的。

名词作主语

例：The villagers didn't realize how serious the pollution was until the fish in the river died.

直到河里的鱼死了，村民们才意识到污染的严重性。

S（subject主语）＋V（verb谓语动词）＋O（object宾语）。主系表结构：S（subject主语）＋V（verb谓语动词，也称为系动词，就是所说的“系”）

倒装：Not until the fish in the river died did the villagers realize how serious the pollution was.

注意：倒装在主句，从句不倒装／did和not提前，只剩动词原形。

Answer 2

回答如下：
英语主语从句的时态不受主句时态的限制，即可以根据动作发生的时间用你所需要的任何时态。例如：
That he is ill is true.
What he said just now is true.
When he will start is not clear.
What you are doing now has something to do with your future life.
Whatever he has done is nothing to me.
How he would make a living was my worry then.