1. Who allowed you to come in here?

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Is 'in' an adverb or a preposition?
Is 'here' a noun or an adverb?

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2. Do not drive, sending text messages.
3. Do not drive and send text messages.
4. Do not drive while sending text messages.
5. Do not drive while you are sending text messages.
6. Do not drive while you send text messages.
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Are they all the same in meaning? Does #2 mean #5 or #6?

In 1, "come in" is a phrasal verb, so "in" is an adverb. The word "here" is an adverb, too. Both words indicate place or direction.

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#4 is the best; #s 5 and 6 are next best; #s 2 and 3 are okay, but not as good as the others.

1. To determine whether "in" is an adverb or a preposition, you can look at how it is used in the sentence. In this case, "in" is used to indicate location or position, which makes it a preposition. "Here" is used to refer to the location or place where the speaker is currently located, which makes it an adverb.

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2. The sentence "Do not drive, sending text messages." is not grammatically correct. It lacks a conjunction or another necessary element to connect the two phrases.

3. The sentence "Do not drive and send text messages." correctly uses the conjunction "and" to connect the two actions of driving and sending text messages. It means that the person should avoid both actions simultaneously.

4. The sentence "Do not drive while sending text messages." uses the conjunction "while" to link the two actions. It means that the person should refrain from sending text messages while operating a vehicle.

5. The sentence "Do not drive while you are sending text messages." uses the conjunction "while" and includes the pronoun "you are" to emphasize that the person should not engage in the act of sending text messages while driving.

6. The sentence "Do not drive while you send text messages." uses the conjunction "while" and omits the word "are" from the previous sentence. It still conveys the same meaning as sentence #5, but with a slightly different structure.

While sentences #4, #5, and #6 have similar meanings, they differ in terms of emphasis and structure. Sentence #2 does not convey the intended meaning and is not equivalent to any of the other options.