一元二次方程x2-2x+1=0的根为______.

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问题:

一元二次方程x2-2x+1=0的根为______.

考点:一元二次方程的解法
题型:填空题

已知△ABC的三个顶点是A(3,-4)、B(0,3)、C(-6,0),求它的三条边所在的直线方程.

题型:填空题

主动脉瓣提前关闭现象常见于()。

A.二尖瓣狭窄

B.主动脉瓣狭窄

C.主动脉瓣关闭不全

D.肥厚型梗阻性心肌病

E.扩张型心肌病

题型:填空题

Part 3


Questions 19-25


·Read thefollowingpassage andanswer questions 19-25.
·For questions 19-25, choose the correct answer A, B, C and D.
·Mark your answers on the Answer Sheet.
Training must have purpose, which is defined a firm analyses of it’s training needs. A review of manpower planing should include a training analysis, which looks carefully at the training at the point of view of the company, its various department and personnel. This may show the weaknesses existing in some departments and that, as a result, training is needed for their staff. Training needs are based on an analysis of the job description and job specification.
A job description should give details of the performance that is required for a specific job, and job specifications should give information about the behavior, knowledge and skills that are expected by an employee who works in it. When all of these have been collected, it is possible to begin the training. This specifies what the training department must teach for the successful performance of the job, and also the best methods to use in the training period.
There are many different training methods, and there are advantages and disadvantages to all of them. Successful training programs depend on an understanding of the difference between learning about skills and training in using them. It is frequently said that learning about skills take place "off the job" in the classroom; but in training in using these skills take place "on the job" by means of such activities as job rotation and planned experience.
It is always difficult to evaluate the cost and savings of a training program. The success of such program depends not only on the methods but also on the quality of the staff that do the training. A company can often check on saving in time and cost by examine the manual work performed by operators and technicians who have completed a training program. The evaluation of management and a supervisory training is much more complex than that. In order to test the result of management and supervisory training, many companies have looked at such things as the number of management and supervisory staff who leave their employment and the number who stay away from the work for the reason of health.

According to the passage, an analysis of training needs is based on ______.

A.the performance required for a general job

B.the work knowledge and skills expected in a person

C.the costs and savings of a training program

D.both the performance and knowledge and skills expected in a job

题型:填空题

一叶轮为8叶片的风机,全压为p,现将叶片减少到6,其他参数不变,则扬程( )。

A.加大
B.减小
C.不变
D.不确定

题型:填空题

根据相关研究,稻田土壤吸附磷化氢浓度最高的地方是在土壤()深度内。

A.0-10厘米

B.10-20厘米

C.20-30厘米

D.30-40厘米

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