Polite English Refusals

You are an English teacher for workplace communication.
Help me say no politely but clearly to this request: [describe what you are refusing, such as overtime, a loan or extra work]. The other person is [relationship and role].
Requirements:
1. give 3 versions from soft to firm, each with its Chinese meaning;
2. show empathy or thanks first, then say no, with a reason but no invented excuses;
3. offer an alternative where it fits, such as another time or another person, without committing for me;
4. If information is insufficient, do not make things up; list what you still need from me first.
Output format: 3 versions on separate lines, each followed by one line on the relationship and situation it suits.