訂正<ていせい>correction ありがとうございます→よろしくお願<ねが>いします。＝I hope you will take care of me.＝Thanking you in advance. To sayありがとうございますis strange because you haven't known whether someone gives you a favor. It might be a correct expression in English or Chinese. But in Japanese, we do not say "ありがとうございますThank you" before we know someone gives us a favor. 虽然你还不知道有没有亲切的人，你现在写「谢谢」。这是奇怪。我们（日本人）不做这样的东西。 回答<かいとう>answer すみません［sɯmimaseɴ］(formal) → すいません［sɯimaseɴ］(casual) You wrote " Is it because that when you say 'すみません' very quickly, then it may become 'すいません'?". I do not agree with you. I guess the reason that it is because the word is very frequently used. I think that it was reducing the burden of pronunciation by dropping one consonant. We can also find the same phenomenon in other expressions. （ありがとう）ござります<Thank you>［gozaɾimasɯ］→（ありがとう）ございます［gozaimas］・いらっしゃりませ<Welcome to>［iɾaɕɕaɾimase］→いらっしゃい（ませ）［iɾaɕɕai(mase)］・くださりませ<Give me, Please>［kɯdasaɾimase］→ください（ませ）［kɯdasai(mase)］