I can't see you on Monday because I have a previous engagement.

星期一我不能见你,因为我有约在先.

《简明英汉词典》

Since you have a previous engagement, why didn't you say so?

既然有事, 何不早说?

《现代汉英综合大词典》

He cannot go for he has a previous engagement.

他不能去,因他已先有约会.

《现代英汉综合大词典》

Owing to a previous engagement, I shan't be able to come.

因事先另有约会, 我无法前来.

《现代英汉综合大词典》

Thanks, but I have a previous engagement.

谢谢, 我已经早有安排了.

轻松英语会话---联想4000词(上)

Sorry. I have a previous engagement.

对不起, 我已经有约了.

轻松英语会话---联想4000词(上)

I am unable to attend because of a previous engagement.

我因有约在先故不能出席.

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I'd love to, but I'm afraid I have a previous engagement.

我很愿意去, 但恐怕已跟别人事先有约.

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I can't go, for I have a previous engagement.

我不能去, 因为我有约在先.

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I cannot see you on Monday because I have a previous engagement.

星期一我不能见你,因为我有约在先了.

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I have a previous engagement at 6: 30.

6点半我先已有约.

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I have a previous engagement.

我已经有约了.

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We have a previous engagement that day.

我们那天有约了.

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I am very sorry that a previous engagement prevents me from accepting your kind invitation.

我很抱歉,因为已另有约会不能接受你的盛情邀请.

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I regret that a previous engagement prevent me from accepting your kind invitation.

我很遗憾之前的约会使我不能接受你善意的邀请.

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