在斜△ABC中,A、B、C、是三个内角,则cotAcotB+cotBcotC+c

题型:填空题

问题:

在斜△ABC中,A、B、C、是三个内角,则cotAcotB+cotBcotC+cotCcotA=(    )。

考点:两角和与差的三角函数及三角恒等变换
题型:填空题

患者男,32岁,因高处坠落致腰背部疼痛、活动受限,双下肢感觉、运动障碍4小时入院,拍X线片示胸11椎体骨折。

若查体时发现股四头肌运动和膝关节内侧皮肤感觉减退,初步判断神经损伤平面为().

A.腰1神经根

B.腰2神经根

C.腰3神经根

D.腰4神经根

E.腰5神经根

F.骶1神经根

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In one sense, we can trace all the problems of the American city back (91) a single starting point: we Americans don’t like our cities very much.
That is, on the (92) of it, absurd. After all, more than three-fourths of us now live in cities, and more are (93) to them every year. We are told that the problems of our cities are (94) more attention in Washington, and scholarship has discovered a whole new (95) in urban studies.
(96) , it is historically true: in the American psychology, the city has been a basically suspect institution, (97) with the corruption of Europe, totally lacking that sense of spaciousness and innocence of the (98) and the rural landscape.
I don’t pretend to be a scholar on the history of the city in American life. But my thirteen years in public (99) , first as an officer of the U. S. Department of Justice, then as Congressman, and now as Mayor of the biggest city in America have taught me (100) too well the fact that a p antiurban attitude (101) consistently through the mainstream of American thinking. Much of the (102) behind the settlement of America was in reaction (103) the conditions in European industrial centers and much of the theory (104) the basis of freedom in America was linked directly to the availability of land and the perfectibility of man outside the corrupt influences of the city.
What has this to do with the predicament of the modern city I think it has (105) to do with it. For the fact is that the United States (106) the federal government, which has historically established our national priorities, has simply never thought that the American city was "worthy" of (107) —at least not to the (108) of expending any basic resources on it.
Antipathy to the city predates the American experience. When industrialization (109) the European working man into the major cities of the continent, books and pamphlets appeared (110) the city as a source of crime, corruption, filth, disease, vice, licentiousness, subversion, and high prices.

A.Nonetheless

B.But

C.Furthermore

D.Although

题型:填空题

大多数生态系统净初级生产量都要通过分解者亚系统渠道,因而呼吸消耗的能量在分解者亚系统明显高于消费者。( )

题型:填空题

《建筑物防雷设计规范》GB50057-2010第3.0.3条第9款规定的人员密集场所,在实际操作时很难把握,例如:一幢建筑物的一至三层为商业,四至十层为办公,属于综合楼,是否按人员密集场所考虑?是否能与有关部门一起制定一个切实可行的措施,对各类建筑物的面积、人数等有一个量化指标,以便更好地执行规范。

题型:填空题

改寄至其它市、县的国内包裹,应按()包裹资例计收改寄费。

A、原收寄局至原投递局

B、原收寄局至新投递局

C、原投递局至新投递局

D、原投递局至新经转局

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