疑问词+to do 是不是只能在宾语从句里用

Question

如题所述

Answer 1

疑问词加动词不定式不一定只能在宾语从句中使用。
疑问词who，whom、what，which，when，where、how和whether（不能用if）后加不定式可构成一种特殊的不定式短语，它在句中可用作主语、宾语、表语等，但不能单独成句。
1)用作主语。如：
When to start has not been decided. 何时动身尚未决定。
How to earn daily bread by my pen was then the problem. 如何靠我的笔吃饭在当时是一难题。
Who to take care of my grandmothers would be a problem. 谁来照顾我的奶奶和外婆会是一个问题。
2)用作宾语。如：
I don’t know what to do. 我不知道该怎么办。
He did not know whether to go there or not. 他不知道是否该去那里。
3)用作表语。如：
The difficulty was how to cross the river. 困难在于如何过河。
The question was where to go. 问题在于到哪儿去。
4)用于双重宾语中的直接宾语。如：
I can tell you where to get this book. 我可以告诉你哪里可以买到此书。
I asked him how to learn English. 我问他如何学习英语。
有时疑问词前可用介系词。如：
I have no idea of how to do it. 我不知道如何做此事。
希望我能帮助你解疑释惑。