Bill has made great progress the help of his teachers.A. for B. with C. under

问题补充：

Bill has made great progress the help of his teachers.

A. for B. with C. under

答案：

解析：for为了，适合于；with 用，随着；under在……之下。句意：在他的老师的帮助下，他取得了巨大进步。老师的帮助与他的进步是伴随而生的，故选B。