Which is

Actually, there's more to this than mentioned in some other answers. The word that is a subordinator; it is not a relative word like who, where, when, or which. Even in integrated relative clauses, they are not always interchangeable. When the relative construction follows a fronted preposition, only relative words will do, so relative pronoun which is available, but that isn't. We have to. Could you please check if the following sentence is grammatically correct: There are a number of reasons for this trend, which is having a significant impact on both family life and on the commun. In earnest writing, the phrase can be used so that Y clarifies X. However, it is a typical witticism (as in your examples) where Y is a cynical statement about X, almost treating X as a setup premise for the humor in Y. Your original is correct as-is, except you need to remove the question mark at the end because it's not a question. What I imagine you are already thinking: The sentence ends with a string of wh- noun clauses. These clauses are not questions, so the last one should also not be a question. Which one is the best is obviously a question format, so it makes sense that which one the best is. It depends. You would use 1. for books in general, without having specific books in mind. You would use 2. for example if you have two books in front of you - in that case, 'which' would really indicate 'which of these two books'. Ironically, you are almost giving another example yourself: Which (of the following sentences) is correct? What is the correct usage? As a preposition, below would be written after information as a stranded preposition. While typically prepositions would precede the noun, stranded prepositions can occur in interrogative or relative clauses, where the interrogative or relative pronoun that is the preposition's complement is moved to the start. We see such a stranded preposition in the case of the information below. When using the word which is it necessary to still use one after asking a question or do which and which one have the same meaning? Where do you draw the line on the difference between which and which one when asking a question that involves more than one answer? Example: How much is 1 + 1? Which (one) is the right answer?: A. 2 B. 11 I should emphasize that the set of possible options can actually be quite large. For instance, when your friend asks what/which class you're taking, either usage is acceptable if we're referring to many possible options. If your friend asked for the class that you were taking to fulfill a requirement in the chemistry department, then 'which' is more appropriate for a more limited set of options. No, it's a matter of grammar. Your first example with a non-defining relative clause example is fine. But that can't be used in non-defining relatives, so in your second example, the that clause should be an independent clause, set apart by heavier punctuation like a semi-colon: I don't like hot weather; that is why I mostly stay in. Because both cats and dogs are plural, “Which are” would be grammatically correct in this case. “Which is” would be used in a singular situation such as “Which is better, blue or green?”. Are is plural while is should be used for singular words.

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