To become a doctor in the United States, students usually attend four years of medical school after they complete college. Then these young doctors work in hospitals for several years to complete a training program called a residency . These medical residents provide hospitals with needed services in return for not much pay. They work under the supervision  of medical professors and more experienced doctors. Medical residents treat patients . they carry out tests. They perform operations. They complete records. In hospitals with few nurses, residents also do work formerly done by nurses. Some medical residents work one-hundred or more hours in a single week. _  Critics   of this system say medical residents work too long and do not get enough res. They say these young doctors may be too tired to perform their medical duties effectively. Now, the government will limit the number of hours of work that residents can work. Most doctors in training will be limited to eighty-four hours of work each week. They will have work periods of no more than twenty-four hours at one time. They will have ten hours of rest between work periods. Medical residents will have one day each week when they do not have to work. Any work they accept outside their hospitals will be limited.Experienced doctors and medical professors will closely supervise the residents to make sure they are not too tired to work. Many medical residents welcomed the work limits. Others, however, said the new policy may interfere with patient care and their own medical education. If a first -year college student in America wants to be a doctor, he has to wait for   _  .
4 years 8 years at least 10 years more than 20 years