Postby thegooseking » February 9th, 2017 6:15 am
DeeLan-san,
First of all, I don't think you want to use the pronoun どれ in your questions. Remember that pronouns replace nouns, but you're using it with the noun トンネル, so you want the "prenominal adjectival" form (to give it its fancy name), which is どの. Strictly speaking, I think どの is an abbreviation of どれの (i.e. using どれ as a の-adjective), which would also work, but it's a lot less common to use the unabbreviated form, so it might sound strange. (You do need to use it unabbreviated if you're pluralising it, but the plural of どれ - どれら - is rarely used, and people tend to just use どれ as both a singular and a plural. So that's really more for これ, それ, あれ. E.g. このトンネル - "this tunnel" but これらのトンネル - "these tunnels".)
Secondly, as far as I can recall, 'unknowns' cannot be the topic of a sentence, so you cannot use question-words (like どの) before a は. So, for the second sentence, you would have to change the は to a が. (Though you're still free to use a は in the first sentence, obviously.)
Thirdly (for completeness), assuming that there are three or more tunnels to choose from, this isn't a correction. But if there are only two, it'd be more common to say どちらのトンネル rather than どのトンネル. どちら literally means "which way?", but it's used for "which" when there are only two choices (kind of like the difference between 'either' and 'any' in English).
As for which is "more correct", they're both grammatically correct (after taking into account what I've said above), but I would say the first one sounds more natural. However, you should maybe take what "sounds natural" to me with a pinch of salt - I'm not an expert on natural-sounding Japanese by any means. I just think the entrance is the topic of the question, so it should come first.
I'm not quite sure how Google Translate got "the tunnel that becomes the entrance" from "which tunnel is the entrance", but trying it myself, I did notice that it only offers that translation if you don't put a question mark on the English question. Adding a question mark, it offers something similar to your second sentence. Sometimes (often) you just need to give Google Translate some help.
小狼