处于病损确立期(established lesion)牙周炎袋壁上皮下方的炎症细胞浸润主要以
A. T淋巴细胞和浆细胞为主
B淋巴细胞和浆细胞为主
C. 巨噬细胞和浆细胞为主
D. 中性粒细胞和浆细胞为主
E. 中性粒细胞和巨噬细胞
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小说离不开对人生世相的描绘,一个阅历不多、涉世不深的作者,是很难在这一领域崭露头角的。诗的创作,特别是许多脍炙人口的诗篇的诞生,大都源于诗人的灵感和天赋。 所以( )。
A. 诗人的年纪一般都比较轻
B. 著名的年轻小说家相对比较少
C. 写诗一般比写小说简单
D. 著名小说家都是中老年人
当今世界科学技术地区发展不平衡,由于国与国、地区与地区、集团与集团之间的科技保密而显得更加突出。然而,科学技术的所有发明创造本应是全人类的财富,任何国家、集团或个人都不应该也不可能长期据为已有。 这段话主要支持了这样一种观点,即( )。
A. 应该加强对科学技术:的保密工作
B. 应该向国外学习先进的科学技术
C. 对科技的保密是有限的,迟早都要泄漏出去
D. 科学技术是全人类的财富,不应该也不可能长期保密
With Airbus’s giant A380 airliner about to take to the skies, you might think planes could not get much bigger and you would be right. For a given design, it turns (1) , there comes a point where the wings become too heavy to generate (2) lift to carry their own weight. (3) a new way of designing and making materials could (4) that problem. Two engineers (5) University College London have devised an innovative way to customise and control the (6) of a material throughout its three dimension al structure.In the (7) of a wing, this would make possible a material that is dense, strong and load-bearing at one end, close to the fuselage, (8) the extremities could be made less dense, lighter and more (9) . It is like making bespoke materials, (10) you can customise the physical properties of every cubic millimetre of a structure.The new technique combines existing technologies in a(n) (11) way. It starts by using finite-element-analysis software, of the type commonly used by engineers, (12) a virtual prototype of the object. The software models the stresses and strains that the object will need to (13) throughout its structure. Using this information it is then (14) to calculate the precise forces acting on millions of smaller subsections of the structure. (15) of these subsections is (16) treated as a separate object with its own set of forces acting on it--and each subsection (17) for a different microstructure to absorb those local forces.Designing so many microstructures manually (18) be a huge task, so the researchers apply an optimisation program, called a genetic algorithm, (19) . This uses a process of randomisation and trial-and-error to search the vast number of possible microstructures to find the most (20) design for each subsection. 9()
A. possible
B. impossible
C. likely
D. unlikely
从地区分布情况看,东、中、西各地区高速公路总量以及所占比重都存在较明显的差异。东部地区共有高速公路10878千米,占全国高速公路总里程的56%;中部地区5014千米,占 25.8%;西部地区3545千米,仅占全国高速公路总里程的18.2%。在各地区的公路总里程中,东部地区高速公路所占比重为2.0%,中部地区为0.9%,西部地区仅为0.6%,中部地区所占比重不到东部地区的一半,西部地区不足东部地区的三分之一。在全国高速公路超过 1000千米的7个省中,东部地区有5个,其中山东超过2000千米,达2077,千米,河北、广东分别超过和达到1500千米,而中、西部地区高速公路超过1000千米的省各只有1个,分别是河南1077千米和四川1144千米。 按照统计资料,山东高速公路里程占本区域的比例约为()。
A. 19%
B. 20%
C. 2l%
D. 22%