he usully goes on（to）（do）his work.
go on with sth= go on to do sth 继续去做另一件事.如果是一个括号呢？如果一个括号，就填doing。go on to dogo on withgo on doing都表示继续做某事。区别是go on to do 是停下来继续去做别的事情go on with 停下来转而做某事goon doing 继续做原来的事情