只有“宾语从句”才注意“时态问题”吗?

所有的名词性从句（主语从句、表语从句、宾语从句、同位语从句）都要考虑时态的问题,如：
It was true that they were true sisters.
The problem was that whom we could get to replace her.
I said that I was very unhappy.
It was a question how he had done it.
当从句为客观真理的时候,时态不变.
The teacher told us that the earth moves around the sun.
It was true that water freezes at thirty-two degrees Fahrenheit.
希望我能帮助你解疑释惑.对，状语从句中则存在“主将从现”的情况，如：If it doesn't rain tomorrow, I will do some shopping.When winter comes, the birds will fly to the south.if和when分别引导条件和时间状语从句，这种情况下存在“主将从现”的情况。希望我能帮助你解疑释惑。