I have doubts about verbs that can take two objects (like give me the key). I am not sure I can leave out one of them in certain cases, and only use the object that refers to a person. Here are some examples: note there are only the objects that refer to people after the verbs.

So you knew that secret. Why didn't you tell me?
I want to see your scar. Why don't you want to show me? - I'll show you later. I haven't even shown my mother yet.
I'll give it to Jenny. - What about me? Will you give me? - Nope, I'll only give Jenny. I promised I'd only give her.

My dictionaries don't help me much when it comes to leave out or include a particle in a structure, Is it necessary to mention the other object too, and say "give it to me", "show it to me", etc.?

Thanks in advance. Emotion: smile
These are idomatic and natural, as you probably know. My sense of it is that sans the original direct object, the original indirect object becomes the direct object. That is, "showing" is something you can do to someone. I don't think it's all that different from "Please take me to the the movies." "Please take me. "Me" is not the indirect object in the first sentence, as it would be in "Please bring me a glass of water.".

I don't mean "show" in the sense of "I'm going to show my horse at the fair." Maybe I'm wrong.

I've never heard "give" used as you suggest in your third example, but the first two are quite natural. (Little kids say, "gimme," but it's sort of an idiom. There's usually a specific direct object in mind.)

Another one like "take me" would be, "Please advise/apprise me of your schedule." Please advise me. Same deal as your examples, but without the indirect object.
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Will you give me? won't work. Most of them won't work. Besides tell and show, I can think of only pay, promise, feed, and serve that work. There are probably a few others.
Note that these are usually impossible without a context that shows what the missing direct object is. That is, you can't just start a conversation with Show the students.
It would be wrong to say: 'Give me it'. The correct sentence is 'Give it to me'.

If you have a noun then it's OK: 'Give me the book' or 'Give the book to me' (to emphasise the addressee of the action).

But some verbs do not admit of the indirect object, e.g. explain the rule to me'. You can't say 'Explain me the rule'. There are also verbs that require the addressee of the action before the the other object without any alternative 'Ask him this question'. It would be incorrect to say 'Ask this question to him.'
Yeah, I should have checked more carefully before posting... because my dictionaries actually seem to help. You can "show somebody", but not "give somebody".
Well, in any case, opinions are always useful, so now I feel more sure thanks to your answers. Thanks! Emotion: smile
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