我儿子年轻时确实有些越轨行为，但现在安下心来，并已结婚成家。 My son did go off the rails for a while in his late teens but he has settled with a family.
我过去绝不会猜到，偏偏是玛丽会行为越轨，竟然背着吉姆与另一个男人幽会。 I would never have guessed that Mary of all people would go off the rails, and her she is seeing another man behind Jim's back.
在聚会后回去的路上，我和我女朋友在我汽车后座上有一点越轨的行为。 On the way back from the party, my girl friend and I had a bit of how's your father on the back seat of my car.
