"저는 방에서 웃습니다."
Translation:I laugh in the room.
It is a very interesting question. So I have made a short research and found this:
So I think, it seems...
that 에 it's for location (at) and 에서 it's where the action take place.
Then, both are locatives used in different situations.
에서 - This is a location where the verb [the action in the sentence] takes place.
X에서 Y까지 - This 에서 is following a different grammatical context and doesn't apply to this rule. Here it is more like a "from X to Y"
에 - This is just a location. Such as a location you are going to or where an item is.
Excellent Explantions, Mr. Ruiz Diaz. If I give more detailed explanations on that; '에' indicates the state with no actions where a person(people) or a thing(things) is(are): I am at home. I am in the kitchen. You are at the zoo. She is on the island. The book is under the table. An airplane is over the mountain. In these sentences, all prepositions like ' at(에), in(안에), on(위에), under(아래에), over(위에), and etc' can be said "에" in Korean. However, when a person or a thing is moving from one place to the other or doing something at that place, then you can always say "에서". Therefore, I am at home ->> I am sleeping at home; 나는 집에 있다. ->> 나는 집에서 자고 있다. The book is under the table. ->>She is reading the book under the table; 그 책은 테이블 아래에 있다--> 그녀는 테이블 아래에서 그 책을 읽고 있다. An airplane is over the mountain.->> An airplane is flying over the mountain; 비행기 한 대가 산 위에 있다. ->> 비행기 한 대가 산 위에서 날고 있다.
I will try my best.
We have first a locative particle, 에서, added to an only place where the action happens. So the form used is X + 에서 .
방 (room) + 에서 (locative particle)
I think the second situation is used for two different locations, X and Y, and perhaps for verbs of movement. But, honestly, I cannot assure that, and I would like to know a better example or more possibilities to apply this form. At the moment, I do not know any example sentence.