You could use either one of those sentences and the listener would understand. The word "yet" simply calls attention to either the current moment, or an implied time in the future. For example: "I'm not ready yet!" - I am not ready, but I will be soon (calling attention to an implied time in the future) "I can't read the second book, I haven't read the first book yet." - I am planning to read the first book, but I haven't had a chance (calling attention to the present). A famous one is children on long car rides asking their parents "Are we there yet?" - Have we arrived at our destination? (Calling attention to the present) It can also be used to convey a sense of urgency. In your example "Have you told Eve yet?" makes it sound like either the listener HAS TO tell Eve at some point in the near future. Hope that helps!

You would say "take the underground". I think this is because when people say "the underground" they're referring to the entire underground rail system as a collective noun (so all the trains, all the lines, as one thing). The word "an" implies one of many, but the underground rail system is the only thing people will be referring to when they talk about "the underground" as a form of travel. Using the word "the" calls attention to the fact that its the only one (or at least, the only one that the speaker would be talking about, which you would figure out from context). The word "a" or "an" makes it sound like its one of many different options. To illustrate this: "We're being invaded! Send the Army!" - "Army" is a collective noun, and there are many "armies" in the world. But from the context, there's only one "army" the speaker would be talking about, and that's the army of their own nation. So in this situation, the speaker would not say "Send an Army!" "I need you to feed the cat tonight" - Cat isn't a collective noun, its a singular noun, but the rule still works. The speaker would almost certainly be referring to the family pet, not any other cat. If they said "feed a cat", that could be taken to mean they want the listener to go out and find ANY random cat and feed it. Hope that helps a bit!

"I am married to Josue" is the correct way to say this.

"Talking about how much you like spaghetti" means "you were telling me about the fact that you really like spaghetti as a food in general"

In both cases, the 'thing' in question comes afterward, so you would never use either of these at the end of a sentence. When you use "regard to" you would always say either "with regard to ____", or "in regard to ____", but never just "regard to ___". Although, just from personal experience, "with regard to" doesn't usually come at the beginning of a sentence. Aside from that, their uses are very very similar. "In regard to your last email, I have sent you the file." "Please confirm your appointment regarding your bank account" "Regarding your enquiry, I am pleased to confirm that your seat on the plane is confirmed."

"The Microsoft Word software" is probably the best one for you to use. "The software: Microsoft Word" can be grammatically correct depending on how you say it (notice the colon). I'd say you're more likely to use that one if they don't already know what Microsoft Word is. You're first telling them that its software, then telling them its called Microsoft Word. It makes the point that the fact that its software is important information for them to know. It also carries a more formal tone, and sounds like something you might use in a piece of academic writing or a formal presentation rather than normal speech. In the first one "The Microsoft Word software", the fact that its software is less important, tagged-on information. Usually in general speech people would just say "Using Microsoft Word", as its so widespread that everyone knows what it is, meaning that there's no need to mention the fact that its software.

Two minor corrections with the second part. "I'm not a teacher but I will help you" ("I will try", not "I'm will try"). Also, the letter "I" when referring to yourself should always be capitalised. So "i'm" should always be "I'm", no matter where it is in the sentence.

Sometimes in speech, when someone is trying to be playful or coy, they might use the word "we" to just mean "you", almost always beginning with "aren't we ___". I don't really know when this started, and it isn't grammatically correct, but people sometimes do it. When he says "Aren't we Mr 'Glass half full'", you are correct, he is only referring to Ross. For example, if you meet your girlfriend for a date you might say "Well, aren't we looking lovely today?" So its used to be playful, but be careful, as I think it can also come across as a little patronising. Like you're talking down to someone a little bit.