"Have you seen my book?"
Translation:क्या तुमने मेरी किताब देखी है ?
I learned that if the direct object takes को, then the transitive verb in the perfective tense is always masculine singular regardless of the gender/number of the object. Could one use को in this sentence? This would make it क्या आपने मेरी किताब को देखा है? Although this is marked wrong by Duoling, would it be grammatically correct? Native speakers or grammar nerds, please.
Yes, the sentence is grammatically correct. But note that the meaning would be closer to 'Have you looked at my book'. Inanimate nouns like kitaab are usually made direct objects of verbs. So, when they're made indirect objects using को, it is to communicate a subtle difference in meaning.
Yes, that makes perfect sense. That is the level of answer I was looking for. I also start getting a clearer idea of when to use को from your comment on how the meaning changes slightly. (I would argue that किताब it is still a direct object, though, and using को with direct objects can make a subtle difference -- sorry for nitpicking...) Anyway: Thanks a l(ing)ot, you are the boss indeed, Vinay!
Both. You can break it down if you want.
The noun phrase is 'my book'. Since किताब is feminine, you need to use the feminine form of 'my'. Therefore, the noun phrase becomes 'मेरी किताब'.
The verb 'to see' in this case has to agree with its object. Its object is the noun phrase 'मेरी किताब' which is feminine so you need to use the feminine form of 'to see' which is देखी.
है goes with all present tense sentences. The only exceptions are sentences with चाहिए where it is dropped and negative sentences with नहीं where it is optional.
When you drop the है in a present perfect tense sentence, it becomes a sentence in the preterite tense.
क्या तुमने मेरी किताब देखी है ? - Have you seen my book?
क्या तुमने मेरी किताब देखी? - Did you see my book?
If you add a था instead of है, it becomes the past perfect tense.
क्या तुमने मेरी किताब देखी थी? - Had you seen my book?
When kya means 'what', it comes right before a verb.
In yes/no questions, 'kya' comes at the beginning. Basically, a statement can be converted into a yes/no question by prefixing it with a kya.
तुमने मेरी किताब देखी है। - You have seen my book.
क्या तुमने मेरी किताब देखी है? - Have you seen my book?