as well as sing, jay is interested in writing music and playing the piano

jay is interested in not only writing music and playing the piano ,but also singing

可以把as well as 改成：aside from / in addition to / besides ，这几个都可以表示“除了 ……外，还有……”，同时还可以把 be interested in改成同意词组：take an interest in
即：
Aside from / In addition to / Besides singing, Jay takes an interest in writing music and playing the piano.

jay is interested in writing music and playing the piano besides singing.

jay is interested in not only writing music and playing the piano ,but also singing