We have reasonable excuse to refuse.

我们完全有理由拒绝。

youdao

She cannot but find a reasonable excuse for her being late.

她不得不给自己的迟到找一个合理的借口。

youdao

Can you give me a reasonable excuse for your being so late?

你能就你的迟到给我一个合理的解释吗？

youdao

But, you know, any reasonable excuse will be entertained.

但其实任何合情合理的理由我都能接受

耶鲁公开课 - 基础物理课程节选

Some penalties might be waived on proof of a reasonable excuse, such as a family illness.

BBC: Tax penalties of ?1,200 sent out by HMRC

The 49-year-old mother, a laundry worker, had denied failing to send her daughter to school without reasonable excuse.

BBC: Edinburgh mother fined ?150 over teenage girl's truancy

One of the byelaws prohibits "people climbing on any wall, fence, tree, barrier, railing or structure without a reasonable excuse".

BBC: New laws to combat 'tombstoning' in East Yorkshire