It's an extremely informal reply that represents an affirmative response. A more formal equivalent would be something like, "Certainly, sir." Some other equally informal equivalents could be things like "No problem" or "You got it."

Yes, it's grammatically correct. All the right elements are in all the right places.

"Alone" is grammatically okay since it can serve as an adverb, but as others have said the meaning could be ambiguous. "On my own" would sound more natural. The Present Perfect tense (or the Present Perfect Continuous tense) is needed in that construction because "since 2022" is a time period that we're still in. A lot of adverbs and adverb phrases trigger the Present Perfect for that reason: recently, lately, in the last few days, etc. I would recommend: I'm learning English on my own. (no time frame is specified) vs. I've been learning English on my own since 2022. ("since 2022" is a time period that we're still in)

Simon gave you the right answer. In "agree to", "to" is the particle of an infinitive verb and it needs to be followed by the base verb to complete the infinitive. In "agree on", "on" is preposition that needs to be followed by a noun or pronoun that serves as the object of the preposition.

1. I'll agree with Dan that "laying" the books would be putting them down flat. Also, in American English we would say "put them on the bookshelf" not "in" it. 2. That's a very formal and poetic way of saying that. The closest thing to saying it that way would be to say "there are eleven hundred miles between the two cities", but it's neither natural nor very clear in meaning. I would recommend: a) The two cities are eleven hundred miles apart. OR b) The distance between the two cities is eleven hundred miles. 3. The best equivalent is "whatever is across from it."

3 is the only one that isn't clumsily worded. 1 has the compound adverb phrase awkwardly placed between the auxiliary verb and the main verb; and it also promises a question, but doesn't actually ask one. 2 is a completely invalid construction. "The question as how to..." simply doesn't collocate well. 4 could be okay grammatically, but only if it referred to one specific question that had previously been asked. From the context, that doesn't seem to be the case.

In your example, "looking through the window" is an adverbial phrase defining the verb "saw." By the way-- you should always capitalize the subject pronoun "I", and you should also insert a comma after "window."

Both of the AI answers copied and pasted below failed to point out that the natural question would be, "What can I do to help?" AI is not the best source for topics with lots of subtlety like grammar and collocations.