先化简,再求值:(2x2﹣4)﹣(2x2﹣5x+6)+(x2﹣5x),其中x=﹣

题型:计算题

问题:

先化简,再求值:(2x2﹣4)﹣(2x2﹣5x+6)+(x2﹣5x),其中x=﹣3.

考点:整式的加减
题型:计算题

下列命题中是假命题的是(  )

A.△ABC中,若∠B=∠C-∠A,则△ABC是直角三角形

B.△ABC中,若a2=(b+c)(b-c),则△ABC是直角三角形

C.△ABC中,若∠A:∠B:∠C=3:4:5,则△ABC是直角三角形

D.△ABC中,若a:b:c=5:4:3,则△ABC是直角三角形

题型:计算题

配电线路和控制线路在敷设时应尽量(),避免穿越不同的防火分区。

A、缩短线路长度

B、增大线路长度

C、缩小线径

D、增大线径

题型:计算题

无机盐缺乏导致疾病的描述中正确的是( )。

A.缺钙可导致婴幼儿的佝偻病

B.缺铁可导致缺铁性贫血

C.缺锌可导致生长发育停滞

D.缺碘可导致甲状腺肿大

E.缺铁可导致老年人骨质软化

题型:计算题

There are a number of formats for reporting research, such as articles to appear in journals, reports addressed to funding agencies, theses or dissertations as part of the requirements for university degrees, and papers to be presented at conferences. These formats differ from one another mostly in their purposes and the audiences whom they address. We will now briefly describe them.

The journal article is a way of reporting research for professional journals or edited collections. The research is reporting in a brief, yet informative way, focusing mostly on the main features of the research such as the purpose, review of the literature (often referred to as "background"), procedures used for carrying out the research accompanied by tables, charts, and graphs, and interpretations of the results (often referred to as discussion).

The content and emphasis of the journal article will vary according to the intended readers (research or practitioners) and it is important for the researcher to be aware of the background and interest of the readers of the journal. Articles intended to be read by practitioners will emphasize the practical implications and recommendations of the research, while articles intended to be read by researchers will describe in detail the method used to collect data, the construction of data collection procedures, and the techniques used for analyzing the data It is important for the novice researcher to be aware of the fact that articles submitted to journals go through a process of evaluation by experts who make a judgment and recommend whether they should be published or not.

The thesis or dissertation is a format for reporting research which graduate students write as part of fulfilling the requirements for an advanced academic degree. The student is expected to describe in great detail all the phases of the research so it can be examined and evaluated carefully by the reader. Thus the thesis or dissertation includes the purpose and significance of the study, the rationale, a thorough review of the literature, detailed information as to the research tools and the procedures involved in their development, a description of data analysis and the results, and an interpretation of the results in the form of conclusions, implications, and recommendation. This detailed description of the process of the research is needed to provide the professors with an indication of the student’s ability to carry out research.

The conference paper is a way of reporting research at conferences, seminars and colloquia. At such meetings research papers are usually presented orally. They are similar to the research article since research is reported in a concise, yet informative way, focusing on the most essential elements of the research. Handouts and transparencies can also accompany the presentations. As with the research article, here too, the content and emphasis of the oral report will depend to a large extent on the type of audience present at the meeting, and whether they are researchers or practitioners.

The common aspect for the journal articles, these and conference papers lies in that()

A. they are all for the practitioners

B. they are all to be read by researchers

C. they are all for being published

D. they are all forms of reporting research

题型:计算题

无线电坑道透视技术直接能查明地质构造的展布和产状不需要做任何补充勘探比如钻探。

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