to be something that you feel you must or must not do, because of your moralprinciples 是原则问题
She couldn’t take the money. It was a matter of principle.
她不能拿这笔钱,这是原则问题。
Examples from the Corpus
be a matter of principle• Dessertis a matter of principle here.• It was a matter of principle.• First, there are matters of principle.• They might have gone higher but this is a matter of principle.• It seemed, as much as anything, to be a matter of principle.