Yes, because they are used to indicate which noun is a subject, technically topic.^^/ Some call them topic markers or topic indicators. \^o^/

Sorry... but I can't understand what you want to know I guess that you are asking " can 은/는 are used after subject?" Only 을/를 can be used after object and 은/는 should be used after subject. And follows are the how to use 은/는 separately. In case of English, You + is/are/am --> "you are" is correct. or He + is/ are/ am --> "He is" is correct. Also in the same manner, you have to choose 은 or 는. But there is very simple rule in Korean grammar. 1. 은 : When it has final consonant - ex) 당신(you) + 은/는 ---> 신 has final consonant (ㄴ) so, have to use 은. 그 사람(he) +은/는 --> 람 has final consonant (ㅁ) so, have to use 은. 2. 는 : When it doesn't have final consonant. - ex) 나 ( I ) + 은/는 --> 나 doesn't have final consonant, so have to use 는. 그녀(she) + 은/는 --> 그녀(녀) doesn't have final consonant, so have to use 는 3. other example - 아버지 (father) + 은/는 --> 아버지은 (x), 아버지는 (o) - 어머니 (mother) + 은/는 --> 어머니은(x) 어머니는 (o) - 형(older brother) + 은/는 --> 형은(o) 형는(x) - 사람 (people) + 은/는 --> 사람은(o) 사람는(x) 3. 을/를 are also same. - 아버지 (father) + 을/ 를 --> 아버지을(x), 아버지는 (o) - 어머니 (mother) +을/ 를 --> 어머니을(x), 어머니는 (o) - 형(older brother) + 을/ 를 --> 형을(o) 형를(x) - 사람 (people) + 을/ 를 --> 사람을(o) 사람를 (x)

Umm...what exactly do you mean?