i dont know which i choose/which to choose速度啊

i dont know which i choose/which to choose速度啊

which to choose
再问： 为什么啊
再答： I don't know what to do. I don't know how to say.
再问： i dont know what you said
再答： “疑问词+不定式动词”结构 英语有个很有用的结构，就是：疑问词+不定式动词（question word + to-infinitive）。 　　疑问词是疑问代词“who, whom, what, which, whose”和疑问副词“when, where, how, why ”。此外，连接词“whether”也适用。 　　“疑问词+不定式动词”结构有何功用呢？其主要功用有下列五种： 　　⑴当主语，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. 　　⑵当宾语，如： ● We must know what to say at a meeting. ● He could not tell whom to trust. ● Do you know how to play bridge? 　　⑶当补足语，如： ● The problem is where to find the financial aid. ● The question is who to elect. 　　⑷当名词同位语，如： ● Tom had no idea which book to read first. ● Do you have a rough impression how to do it? 　　⑸当宾语补足语，如： ● Jim is not sure whose to choose. ● Mary and John are not certain whether to get married or not. 　　适用于“疑问词+不定式动词”的动词包括：“know, see, decide, tell, ask, consider, discover, explain, forget, guess, hear, imagine, inquire, learn, remember, think, wonder, understand”等。 　　有点值得特别注意的是：当这结构当宾语时，它的作用等于名词分句，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. 　　有些动词，如“ask, show, tell, advise, inform, teach”等，可以先有个宾语，然后才接着加上适当的“疑问词+不定式动词” 结构。例如： ● The chief technician showed the apprentice how to repair the machine. ● Have you told him where to get the application form? 　　综上所述，可见“疑问词+不定式动词”结构是个形象清新，既容易用又不容易出错的特别结构，可以多多运用。