Nancy is often seen-------(hang) out on weekends.to hang

e seen to do sth 意思就是说过去被看见做什么事情.也许一般我们会认为see的句型只有see sb.do sth./see sb.doing sth,但要注意这里是被动语态：is seen,被动的也有两种句型：be seen to do / be seen doing