"Are you cold? Take my jacket!"
Translation:Ist dir kalt? Nimm meine Jacke!
In German you don't ask if "[you] are cold" - that would be like asking if your body is cold like a corpse. Instead, you ask if "it is cold to [you]": Ist es dir kalt? The dative case for "you" basically means "to you", and is hence asking more how you feel about the temperature, rather than about the actual temperature of your body. Even when the weather is cold, your body usually regulates its temperature quite effectively, unless you have hypothermia.
No, I think it's fine.
es here is a dummy object that's only needed to "fill the space" before a verb in a statement; if there is something already before the verb (e.g. mir) or of it's a question and the verb can go right at the beginning, the es is not needed and so is not present.
ist es dir kalt? sounds wrong to me.
"Ihnen" needs to be capitalized, or else it means "them." But I don't think Duo checks for correct capitalization, so probably you had a mistake elsewhere in your answer. What was the rest of your answer?
(The correct version with formal "you" is "Ist Ihnen kalt? Nehmen Sie meine Jacke.")
Ja, "Hast du Kalt" ist wirklich falsch.
The construct "hast du . . ." means "do you have . . . ", so you would be saying "do you have Kalt?" But Kalt is not a noun. It almost sounds as if you would be saying "do you have
a cold?", but that is not what's meant here ("a cold" being an illness).
The similarity between "cold" as an adjective and "cold" as a noun may be causing confusion, so change the question a little to "are you hot?" One wouldn't say "have you hot" oder "hast du heiß".
"gibt es" is often used when you are talking about something in general. Like are there cookies. As in if you dont know who may have put cookies there but you think someone might. "Ist es dir kalt" sounds more natural, but I think most germans would understand what you mean if you used gibt.
The following is a quote from this website: http://www.nthuleen.com/teach/grammar/reflexexpl.html
In statements, the reflexive pronoun should occur directly after the conjugated verb, or as close to the subject as possible (while maintaining verb-second word order).
Ich wasche mir jeden Tag die Haare.
Jeden Tag wasche ich mir die Haare.
Ich habe mir heute die Haare gewaschen.
Ich kann mir heute die Haare nicht waschen.
In questions, the same rule applies: the reflexive pronoun stays as close to the subject as possible, allowing for correct verb placement.
Putzt du dir jetzt die Zähne?
Soll ich mir die Zähne putzen?
Hast du dir die Zähne geputzt?
In this question, It is 2 persons. One is asking the other "Are you cold?" "Take my jacket" So If I wrote the translation in German "Bist du kalt?" it should be accepted because it involves 2 persons. And the other reply is "Nimm meine Jacke!" for "Take my jacket!" which means they know each other personally... If it were a person which you didn't know or in a group then "Sind Sie kalt?" because it is formal and not 2 persons. and I would reply for "Take my jacket!" in german Formally "Nehmen Sie meinen Jacke!" because it is Formal. Lernt that in Language School.