"situation" 指的是 "place of employment"
很遺憾我不得不離開這個給了我很多關懷與友誼的部門。
5. my experience at abc company has been both educational and rewarding*.
"rewarding" 即satisfying
我在abc公司的經歷既有教育意義，又令人滿意。
6. however, i find it absolutely necessary to seek an appointment* which can enable me to earn a higher salary to cope with the growing high cost of living.
"appointment" 和 "situation"一字相仿 , 代表 a place of employment 或 a job之意
然而我覺得有必要更換工作，以便賺取更高的薪水來應付日益增長的生活消費指數。
7. i take this opportunity to * thank you for the wonderful experience i had with abc company.
另一表達方式: "i take this opportunity of thanking you for the wonderful experience i had with abc company,"
藉此機會，為我在abc公司的愉快經歷向您表示感謝。
8. i have concluded that i can no longer function * effectively when the policies followed by the headquarters * fail to provide the support i need as a regional manager.
"function"即 operate 或 carry on one's duty; "headquarters" 總是以複數形式出現, 代表 the administrative center of an enterprise 之意
我已經下了結論，當總部執行的政策無法為我這位地區經理提供必要的支持，我將無法有效地勝任這個職位。
9. please let me know if there is anything i can do to make my departure a smooth one *.
"one" 是代詞, 指代前面的名詞 " departure"; 它有時也可指代後面的名詞 , 如: "the basketball players who score the most are not always the ones with the best brains."