这个是主谓一致原则
当主语后面有由 as well as .in addition to .with .along with.together with.except等引导的词组时,其后的动词形式取决于主语本身的形式.
例如：the manager with some workers was working during the holidays.
the father ,as well as his sons ,is going to enroll.
Bill .together with his sisters,was hurt in the accident