which to choose為什么啊I don't know what to do.I don't know how to say.i dont know what you said“疑問(wèn)詞+不定式動(dòng)詞”結(jié)構(gòu)英語(yǔ)有個(gè)很有用的結(jié)構(gòu)，就是：疑問(wèn)詞+不定式動(dòng)詞（question word + to-infinitive）。 　　疑問(wèn)詞是疑問(wèn)代詞“who, whom, what, which, whose”和疑問(wèn)副詞“when, where, how, why ”。此外，連接詞“whether”也適用。 　　“疑問(wèn)詞+不定式動(dòng)詞”結(jié)構(gòu)有何功用呢？其主要功用有下列五種： 　?、女?dāng)主語(yǔ)，如： ● When to hold the meeting has not yet been decided. ● Where to live is a problem. ● How to cope with the rising cost of living becomes a daily discussion topic. 　?、飘?dāng)賓語(yǔ)，如： ● We must know what to say at a meeting. ● He could not tell whom to trust. ● Do you know how to play bridge? 　?、钱?dāng)補(bǔ)足語(yǔ)，如： ● The problem is where to find the financial aid. ● The question is who to elect. 　?、犬?dāng)名詞同位語(yǔ)，如： ● Tom had no idea which book to read first. ● Do you have a rough impression how to do it? 　　⑸當(dāng)賓語(yǔ)補(bǔ)足語(yǔ)，如： ● Jim is not sure whose to choose. ● Mary and John are not certain whether to get married or not. 　　適用于“疑問(wèn)詞+不定式動(dòng)詞”的動(dòng)詞包括：“know, see, decide, tell, ask, consider, discover, explain, forget, guess, hear, imagine, inquire, learn, remember, think, wonder, understand”等。 　　有點(diǎn)值得特別注意的是：當(dāng)這結(jié)構(gòu)當(dāng)賓語(yǔ)時(shí)，它的作用等于名詞分句，例如： ● I could not decide which dictonary to buy. ＝I could not decide which dictionary I should buy. ● Jack did not know where to find such a good teacher.＝Jack did not know where he could find such a good teacher. 　　有些動(dòng)詞，如“ask, show, tell, advise, inform, teach”等，可以先有個(gè)賓語(yǔ)，然后才接著加上適當(dāng)?shù)摹耙蓡?wèn)詞+不定式動(dòng)詞” 結(jié)構(gòu)。例如： ● The chief technician showed the apprentice how to repair the machine. ● Have you told him where to get the application form? 　　綜上所述，可見“疑問(wèn)詞+不定式動(dòng)詞”結(jié)構(gòu)是個(gè)形象清新，既容易用又不容易出錯(cuò)的特別結(jié)構(gòu)，可以多多運(yùn)用。