My question is [STRIKE]great[/STRIKE] very simple and easy to understand. What is the differences between "that" and "this"? In my dictionaries, they are same.
You must be looking at Chinese-English dictionaries which tell you they
translate the same. Look them up in an English dictionary and you'll see they are not.
The difference between
this and
that is complicated. They both "point" at something. In the simplest case, "this" refers to something nearby and "that" to something further away. For example, if a jeweler is showing you rings on the counter in front of you, you might say "I don't like
this one" (the one right in front of me). "Can you show me
that one over there in the window?" You'd point across the room at the one you're interested in.
When these words refer to text, the same relationship applies: "this" means "the words that are close by" and "that" means "the words that are further away".
We've had a number of threads discussing this issue. It's very hard for learners to master the difference when their native languages don't have similar words.