Definition: used to say that you are sure something is true Level: C2
我发誓我离开时锁了前门。
I could have ___sworn that I locked the front door when I left.
我敢肯定我今天早上在厨房桌子上看到你的钥匙了。
I could have ___sworn I saw your keys on the kitchen table this morning.
他发誓他告诉过我关于会议的事，但我一点印象都没有。
He ___swore he had told me about the meeting, but I had no memory of it.
