翻译成英文：总统在什么地方发表演说尚未决定。（主语从句）

It has not been decided where the president makes the speech.

It是形式主语
真正主语是where the president makes the speech

希望帮上忙

It is not decided where the president will give a speech.注意这里是主语从句，只不过放在了后面，用it代替了

the president has not decided where to make the speech

Where the president will give a speech is not decided.

Where's speech has not been decided yet.