I had to refuse because of a prior engagement.
我因为已经有预约只好拒绝了。
She will be unable to attend because of a prior engagement.
因事先有别的安排，她将不能出席。
I have a prior engagement at five.
我已经先有一个在五点钟的约会。
A prior engagement precludes my coming to your party.
先前的一个约会使我不能参加你的宴会。
I'm sorry, but I have a prior engagement for that evening.
对不起，我那天晚上已经提前预约了。
I was unable to attend the wedding because of a prior engagement.
我因有约会在先而未能参加婚礼。
They had to refuse the dinner invitation because of a prior engagement.
他们不得不拒绝晚餐邀请，因为他们之前已经另有约会。
I fear that a prior engagement will prohibit me from joining you in dinner.
我有约在先，恐怕不能与你共进晚餐。
I sincerely regret that owing to a prior engagement I am obliged to decline your kind invitation to dinner next Saturday.
由于有约在先，我不能接受下星期六与您共进晚餐的邀请，对此深表遗憾。
I sincerely regret that owing to a prior engagement I am obliged to decline your kind invitation to dinner next Saturday.
由于有约在先，我不能接受下星期六与您共进晚餐的邀请，对此深表遗憾。
应用推荐