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【简答题】
[A] As more has become known of the many thousands of African plant species and their complex ecology, naming, classification, and mapping have also become more particular, stressing what was actually present rather than postulating about climatic potential. [B] In regions of higher rainfall, such as eastern Africa, savanna vegetation is maintained by periodic fires. Consuming dry grass at the end of the rainy season, the fires burn back the forest vegetation, check the invasion of trees and shrubs, and stimulate new grass growth. [C] Once, as with the scientific treatment of African soils, a much greater uniformity was attributed to the vegetation than would have been generally accepted in the same period for treatments of the lands of western Europe or the United States. [D] The vegetational map of Africa and general vegetation groupings used here follow the White map and its extensive annotations. [E] African vegetation zones are closely linked to climatic zones, with the same zones occurring both north and south of the equator in broadly similar patterns. As with climatic zones, differences in the amount and seasonal distribution of precipitation constitute the most important influence on the development of vegetation. [F] Nevertheless, in broad terms, climate remains the dominant control over vegetation. Zonal belts of precipitation, reflection latitude and contrasting exposure to the Atlantic and Indian oceans and their currents, give some reality to related belts of vegetation. [G] The span of human occupation in Africa is believed to exceed that of any other continent. All the resultant activities have tended, on balance, to reduce tree cover and increase grassland but there has been considerable dispute among scholars concerning the natural versus human-caused development of most African grasslands at the regional level.
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【单选题】决定窗体有无控制菜单的属性是()
A.
controlbox
B.
minbutton
C.
enabled
D.
maxbutton
【单选题】决定窗体有无控制菜单的属性是 。
A.
MinButton
B.
Enabled
C.
MaxButton
D.
MaxButton
E.
ControlButton
F.
MaxButton
【单选题】从一个已知高程点开始沿一条水准测量路线测量最后再回到A点,这种水准路线称为()水准路线。
A.
附合
B.
闭合
C.
D.
连续
【多选题】污水提升泵站主泵选型需符合以下要求()。
A.
在平均扬程时,水泵应在低效区运行;在最高与最低扬程时,水泵能安全、稳定运行,排水泵站的主泵,在确保安全运行的前提下,其设计流量按量小单位流量计算
B.
由多泥沙水源取水时,记录泥沙含量、粒径对水泵性能的影响;水源介质有腐蚀性时,水泵叶轮及过流部件应有防腐措施
C.
新设计的水泵必须经过模型试验或装置模型试验,经鉴定合格后,可采用
D.
具有多种泵可选择时,综合分析水利性能、机组造价、工程投资和运行检修等因素择优确定
E.
满足泵站设计流量、设计扬程及不同时期排水的要求
【简答题】这条线( )测量。
【单选题】法国历史学家亨利•高第说:“我并不认为这在当时是个好办法。我们这样做了,就使得中国人感觉到,我们才是真正的野蛮人。此外,对同胞无辜的血,我们也不应该向石头寻仇。法国人与其英国同盟军的分歧就在这一点上:抢劫,可以;放火,不行! ”亨利•高第所评价的历史事件是( )
A.
英军武力强占香港岛
B.
英法联军火烧圆明园
C.
八国联军洗劫北京城
D.
列强瓜分中国的狂潮
【单选题】决定窗体有无控制菜单的属性是 。
A.
MinButton
B.
Enabled
C.
MaxButton
D.
ControlButton
【单选题】决定窗体有无控制菜单的属性是
A.
ControlBox
B.
MinButton
C.
Enabled
D.
MaxButton
【简答题】影响硅酸盐水泥体积安定性的主要因素有 含量、 含量及SO3的含量,它们分别采用 、压蒸发法进行检验。
【单选题】 零件的压强 p 不大于零件的许用压强P 是 准则的表达式。
A.
强度
B.
刚度
C.
耐磨性
D.
韧性
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