"은/는 and 이/가" Which of them to use has nothing to do with whether the sentence ends with a verb or adjective. Here's a simple introduction that might help. The basic rule is that 은/는 is generally used to talk about important, open information as a main topic. 이/가 on the other hand is more for supplying a specific fact, in a closed manner, playing a subordinate role ("open" here means it has a nuance of wanting to talk more about it, while "closed" indicates it ends there). 은/는 is generally called a topic marker to distinguish it from 이/가 which is a strict subject marker. Examples: - 나는 이 학교를 다녔다: I attended this school. It introduces new info about the main topic 나, so 는. - 이것은 내가 다닌 학교다: This is the school I attended. 나(내) is in a sub-clause modifying 학교, so 가. (이것 is the main topic the speaker wants to talk about, and 내가 is supplying a single fact in a subordinate role) - 그가 왔을 때 나는 자고 있었다. When he arrived, I was sleeping. (typical sub- and main clause arrangement: 이/가 in sub-clause, 은/는 in main) AA: 누가 숙제를 다 했어요? Speaker wants to know a specific fact only, WHO finished the homework. BB: 영수가 댜 했어요: Same. A single specific fact is given as an answer to a question asking for it. AA: 철수는 아직 못했나요? Speaker draws attention to a new person, who becomes a new topic. So, in subordinates phrases, it is typically 이/가: 내가 너를 좋아하는 이유, 내가 읽던 책, 정보가 중요한 시대, etc. When one talks about something as a min topic, it is with 은/는: 나는 네가 좋아, 난 회사 그만 두기로 했어, 그 애는 죽었어. Knowing these basic principles would be a good start for beginners.

Nuance can be different both verb and adjective can come after subject with 은/는/이/가 for example. 펭귄은 귀엽다. >> 'cute' is adjective 펭귄은 수영을 한다. >> 'swim' is verb 철수는 키가 크다 >> 'tall' is adjective. 철수는 학교에 간다 >> 'go' is verb. 펭귄이 크다 >> 'big' is adjective 펭귄이 알을 낳는다 >> 'lay' is verb 철수가 아프다 >> 'sick' is adjective 철수가 밥을 먹는다 >> 'eat' is verb if you say 은/는, it's like whay you say is ordinary fact. if you say 이/가, it's like special case or what you say wasn't supposed to happen but happened.

Let’s look at both 은/는 and 이/가 at the same time. 은/는 and 이/가 are probably the two (but I think they should be looked at as one) most challenging and confusing grammar points for Korean learners and are the most frequently asked about (since they come up very early in one’s Korean studies). This is because there are no clear cut rules for them, as they are highly contextual. They also seem to be used very similarly. There are, however, some general guidelines that can be used to give you an idea of which one to use. My advice about 은/는 and 이/가 is this: 1. Think of them as a pair or unit. They go together. They’re similar. If you’re not using the one, you’re using the other. 2. Don’t stress about which one to use. Just go with the flow and get corrections. Practice listening and reading and noticing them. Get a feel for which one is correct in a situation. 3. There are no hard and fast rules! So let’s take a look at these “general guidelines”: 1. 이/가 a. Used when making descriptions b. Used when introducing a new subject/topic c. Used when talking about something general d. Used to provide emphasis on the noun it’s attached to 2. 은/는 a. Used when making comparisons b. Used when continuing to talk about an already mentioned subject/topic ("as for", "when it comes to") c. Used when talking about something specific d. Used to provide emphasis on the rest of the sentence

You should pay attention to the specific grammar or vocabulary you’re using in a sentence, as they may come with a set usage of a certain particle. Some grammar patterns will use one of 이/가 or 은/는 and it’s unrelated to these guidelines. If you can remember and understand these guidelines, you should do a pretty decent job at using these two particles! Just don’t stress! Of course, where would we be if we didn’t look at some examples?  1. 날씨가 어때요? 음, 날씨는 눈이 많이 와요. How is the weather? Umm, as for the weather, it's snowing a lot. 2. 저는 한국어를 공부해요. 그런데 스페인어는 안 해요. I study Korean. However, when it comes to Spanish, I don't (study it).

Ah, the biggest challenge and most commonly asked question for Korean learners :) The rule is - there are no rules! Knowing which of these two to use by trying to learn some trick is impossible - it's highly contextual. (And trying to learn which to use based on the name of the particle is largely pointless). Only you can know which is right! Well, Koreans will notice too if it's obviously wrong. There are some general guidelines...I think for just starting off basically, that's not the worst description, but it's far from correct because both can be used with verbs and adjectives. However, 이/가 tends to be used in basic, general descriptions (hence that notion you have). Some grammar patterns will just be set up to use one of the other. Here: