Jim as well as Jack has been punished for their bad behavior

Both and has

as well as 在这里是和的意思，但如果句子用到as well as，该句的谓语要与as well as 前面的主语保持一致，它前面的这个主语是单数，谓语就用单数，是复数谓语就用复数。
但both and 的这个搭配，谓语永远用复数。

Both jim and jack has been punished for their bad behavior.

not only;but also;has.