Plagiarism and cheating on tests are not only unfair to students who do their own work, but are also detrimental to a university's reputation and the worth of its diploma. 老师您好，请问这句话中，but后面的are可以省略吗？我总觉得unfair to和detrimental to可以共用一个（not only前面的）are呢。but后面的are是不是多余的呢？求解，谢谢老师～