What's the difference between 이 and 이것 ?
When do i use 이/그?
이 is this, and 그 is that when it is close to the speaker.
그 when it is close to the listener, away from the speaker. Cmiiw.
how do you know when it is close or far away from the speaker?
If it is close to the speaker they will say 이. In that case you as the listener will say 그 about the same object
It's the same way in english. You say this, that, over there and etc based on where you and the object are