Can you teach me the ways to quote the one below, which is pretended to have been spoken by Joe, including ways to quote partially and selectively?

Hypothetical quotational content (not necessarily true):
Joe: "A lot of Chinese I saw seem to worry too much for too long for no good reasons."

Can I quote partially to report this? How can one use it to incorporate into my writing in newspaper context and formal writing context or informal writing context?
You mean like this?

Joe expressed his belief that there is excessive worrying on the part of many Chinese "for no good reasons."
Thank you. I think thee original quote limited the Chinese to those he met, but your version didn't state that. Is that OK? How much can a person omit?

Can a person tweak the content a little bit more than what you seemed to have done and be OK?

Some thing like this OK?
Joe expressed his belief that a small portion of Chinese are worrying to an uncomfortable degree "for no good reason."
Teachers: We supply a list of EFL job vacancies
Actually, your restatement gives an unintended meaning.

Go back to mine and just and "he enountered" after the word "Chinese." My omission was not intentional.

Joe talked to at least a few people, and most of them are worried. Joe may assume that if he talked to a million people, most of them would be worried. He may be thinking that most Chinese in general are worried. In your restatement, you refer to "a small portion of Chinese" -- that gives a very different view. That implies that if he talked to a million people, only a few would be worried.

You can omit what is not relevant. This would NOT be okay:

Joe: The Times is a good paper. It's reliable, it's reputable, it's accurate. The Record is a piece of trash, frequently distorting the truth.

The reporter from the Record writes: In comments that included references to the Times, Joe even used the phrase "a piece of trash."
Thank you again.

I think in a thread named "quoting partially," I believe Clive have said something in the line of a person reading a text should decide how much is omitted and it's difficult to find out whether a piece of report is accurately bringing? out a direct quote. And he seemed to have given an interesting example.

Can a person do this with this made-up quote, which is similar in content and structure to what Clive gave (I think)?

A: I will give you the amount of money you asked only if you give me a bucket of water.

1.We have good news. A has agreed to give us the money.
2.We have good news. A has agreed to give us the money as soon as possible.
3.We have good news. A has said that he "will give us the amount money we asked."
4.We have good news. A has said that he will give us "the amount of money we asked."

Would you say what is in quotes have to be one-hundred percent, unchanged content -- even pronouns like 'he' or 'she'?
None of those would be acceptable - all omit the cruicial elements of "only if you give me a bucket of water."

There are only a few times you need to use direct quotes outside of journalism. Otherwise, we go with reported speech.
Students: Are you brave enough to let our tutors analyse your pronunciation?
if you're changing a pronoun in a quote, then you put the changed part in brackets. for example, the statement "I will love her forever and ever," might be quoted by someone else as "[He] will love her forever and ever." Another example would be if the quote you're using uses "he," "she," or "they," instead of the proper name and the proper name has not been mentioned before, it is acceptable to use brackets and replace the pronoun with the proper noun. i.e. "He won the game single-handedly," could be changed to, "[Joe Schmoe] won the game single-handedly."