DearSirs, MywifeandIwereverygratefultoreceiveaninvitationtoattendthecelebrationsmarkingtheopeningofyournewfactory.Wearesorrytoinformyouthatwehavetodeclineyourinvitationowingtoapreviousengagement. Yoursfaithfully, 中文对照 敬启者: 我和夫人非常感谢阁下邀请参加贵公司新建工厂开业典礼庆祝仪式。但由于事先有约,无法应邀前来参加,深表遗憾。 敬上