I apologize in advance for the long post, but I have some questions and assumptions I'm not sure about regarding ている. I know it means three things (well, possibly more, but three that I know so far)- 1. Ongoing action, 2. Ongoing state after a certain action, and 3. Something done habitually, but I'm unsure about some nuances, mostly regarding how to know which is which.
First of all, am I correct in assuming that version 3 will always be recognizable by context? Like if you say お茶を飲んでいます while not drinking tea, it will immediately be implied that it's something you do regularly? Or when a day and/or time is in the sentence, it will also immediately mean a habit? And if context ISN'T always enough, then how do you tell?
Next, is there any real difference between, for instance, 食べました and 食べていました? I assume it's like "I ate" vs "I was eating", which is more or less the same, but is there a specific nuance in Japanese as to which conjugation should be used? (This general question probably also applies to non-past tense)
And my biggest issue, how do I differentiate between versions 1 and 2? I know in the lesson, it points out activity verbs vs change verbs, but then it gives the example sentence 友達はうちに来ています and says it means that the friend has already come and is currently at the house. I can't quite wrap my head around that one. To me, it reads as "(A) friend is coming to (the) house", because as far as I can tell, nothing even implies a stay at the house (maybe the friends are just meeting there and then going to immediately go somewhere else together). Also, to me, "coming" feels like something that can be, in fact has to be, done for an extended period of time; it can't just go from "hasn't come" to "already came" because the word itself is an action\activity. In various quiz sentences with different words, too, I'll often misread them as an active action when they apparently aren't. Plus things like "to open" and "to shut" could also easily be either 'activity' OR 'change' verbs... So how do I tell the difference between the two versions of ている?
Also, what does version 2 mean when past-tense or future-tense? Is it saying that the named action has happened\will happen, or the ongoing state resulting afterward has happened/will happen? I know it probably amounts to about the same thing, but which is being focused on in that case?
Again, I apologize for the long post, and if there are any other little nuances or anything like this that you suspect I'll stumble into issues with later, please do let me know about that as well. ありがとうございます
