Being polite and humble is so, so important when you're learning another language. The following phrases and expressions will help you ease into conversation with anyone and everyone you interact with, or alleviate any tension at school or in the office.
ありがとうございます arigatou gozaimasu – Thank you.
どういたしまして douitashimashite – You're welcome.
問題ないよ mondai nai yo – No problem.
ください kudasai – Please (requesting)
どうぞ douzo – Please (offering)
お疲れ様です otsukaresama desu – Thank you for your efforts.
失礼します shitsurei shimasu – Excuse me (for my rudeness).
すみません sumimasen – Excuse me.
ごめんなさい gomen nasai – I'm sorry.