1. occasionally2. occasional3. incidentally例句与用法: 1. 他偶然说走嘴。 He had a slip of tongue by accident. 2. 我只是偶然抽一支雪茄。 I only smoke an occasional cigar. 3. 他偶然发现了这幅画。 He discovered the painting perchance. 4. 我们的相遇是很偶然的。 Our meeting was quite accidental. 5. 我偶然跟他闲聊, 一起说笑话. He's someone I have an occasional chat and joke with. 6. 我遇见她完全是偶然的. I met her quite by chance. 7. 我们(彼此)相遇纯属偶然. We met (each other) quite by chance. 8. 我们只是在昨天才与她偶然相遇. We met her only yesterday, as it happens.