He had his wallet stolen on the bus.

had 是动词 have 的过去式，在这里表示"遭遇、经历"某种情况。 wallet 是名词，指"钱包"，通常用来装现金、银行卡等个人物品。 had his wallet stolen 这个结构表示"遭遇钱包被偷的情况"，强调被动遭受的经历。