推荐阅读：Dear Sirs， My wife and I were very grateful to receive an invitation to attend the celebrations marking the opening of your new factory．We are sorry to inform you that we have to decline your invitation owing to a previous engagement． Y
Dear
Sirs，
My
wife
and
I
were
very
grateful
to
receive
an
invitation
to
attend
the
celebrations
marking
the
opening
of
your
new
factory．We
are
sorry
to
inform
you
that
we
have
to
decline
your
invitation
owing
to
a
previous
engagement．
Yours
faithfully，
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
