Questions 61 - 65 are based on the following passage. 　　Alarmed by a 20-year decline in student achievement, American schools are considering major upheavals in the career structure of teachers, school boards around the country are planning to abandon traditional salary schedules and single out outstanding teachers for massive pay rise. 　　The idea is regarded with deep suspicion by the United States’ biggest teachers’ unions, the National Education Association and the American Federation of Teachers. They say the creation of a cadre of elite teachers will sour professional relationships and encourage teachers to compete instead of cooperate; they also question whether a fair way can be devised to tell which teachers really do perform better than their colleagues. 　　But heightened public anxiety about secondary education appears to have given the master teacher concept unstoppable political momentum. Florida and Tennessee are racing to introduce ambitious statewide master teacher schemes before the end of the year. Less grandiose proposals to pay teachers on the basis of merit instead of seniority have already been implemented in countless school districts. And the Secretary of Education, Mr. Terrel Bell, recently promised substantial incentive grants to states which intend to follow their example. 　　Low pay is believed to be the single most important reason for the flight from teaching. The average salary of a teacher in the United States is just under $19,000, much less than that of an engineer ($34,700) and not much more than that of a secretary($16,500). To make ends meet it is common for teachers to take second jobs in the evening and in their summer holidays, and women, who used to make up the bulk of teacher candidates are turning to better paid professions. 　　The unions insist that the answer to this problem is to increase the basic pay of all teachers, but most states would find that too expensive, they would be better able to afford schemes that confine pay increases to a small number of exceptional teachers. Champions of the idea say it would at least hold out the promise of high pay and status to bright graduates who are confident of their ability to do well in the classroom, but are deterred by the present meager opportunities for promotion. 　　One of the first large-scale tests of this approach will come in Tennessee, where a year of painstaking negotiations has just overcome bitter union opposition to a wide-ranging master teacher scheme. Tennessee promised that they will allocate $300 million as education budget. In return for a chance to earn bigger salaries and faster promotion, teachers will subject themselves to closer scrutiny. 　　The Tennessee plan will make it harder for poor teachers to join the profession. Beginners will have to serve a probationary year before qualifying, and another three apprentice years before receiving tenure. Apprentice teachers who fail to reach a required standard will not be allowed to stay on. Survivors will be designated “career teachers” and given a chance to climb through three career rugs and earn bonuses of up to $7,000. Advancement will not be automatic. The performance of each teacher will be closely assessed by committees of teachers drawn from other districts. 　　Questions: What is the main idea of the text