(1)Very Formal 非常正规的(例如给政府官员的)
Respectfully yours , / Yours respectfully,
(2)Formal 正规的(例如客户公司之间)
Very truly yours, / Yours very truly, / Yours truly,
(3)Less Formal 不太正规的(例如客户)
Sincerely yours, / Yours sincerely, / Sincerely,
Cordially yours, / Yours cordially, / Cordially,
(4)Informal 非正规的(例如朋友,同事之类)
Regards, / Warm regards, /With kindest regards, / With my best regards,
My best, / Give my best to Mary, Thanks, / See you next week!