| Trees are useful to man in three
important ways: they provide him with wood and other products; they give him
shade; and they help to prevent droughts and floods. Unfortunately, in many parts of the world, man has not realized that the third of these services is the most important. (78) {{U}}In his eagerness to make money from trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had. {{/U}}And besides, he is usually too careless to plant and look after new trees. So the forests slowly disappear. This does not only mean that man will have fewer trees. The results are even more serious: for where there are trees, their roots break up soil--allowing the rain to sink in--and also bind the soil, thus preventing it from being washed away easily; but where there are no A. New trees are not looked after properly. B. Many trees have been cut down by man. C. Man has not paid enough attention to planting trees. D. All of the above. [名词解释]雅典“宪法”
[单项选择]氧气浓度低于（）时，一般不会发生瓦斯爆炸。
A. 12% B. 15% C. 20% D. 25% [判断题]中间站调车，应使用有示意图的调车作业通知单。（）
A.正确 B.错误 [多项选择]空想社会主义理论的合理性表现在（ ）
A. 它深刻揭露了资本主义的罪恶 B. 它认为资本主义必须要为一种更好的制度取代 C. 它揭示了资本主义必然灭亡的经济根源 D. 它认为无产阶段是埋葬资本主义的革命力量 [单选题]The WHO says there is currently no evidence of human-to-human ______ of the virus.
A.translation B.transition C.transmission D.transaction [判断题]信号集中监测系统开关量输入板的英文符号是KC。
A.正确 B.错误 [单选题]信息系统安全保护法律规范的基本原则是（ ）。
A.谁主管谁负责的原则、突出重点的原则、预防为主的原则、安全审计的原则和风险管理的原则 B.突出重点的原则、预防为主的原则、安全审计的原则和风险管理的原则 C.谁主管谁负责的原则、预防为主的原则、安全审计的原则和风险管理的原则 D.谁主管谁负责的原则、突出重点的原则、安全审计的原则和风险管理的原则 [单项选择]样品在放置期间，待测组分浓度的影响因素是（）
A. 生物因素 B. 化学因素 C. 生物、化学和物理因素 D. 生物和物理因素 E. 物理因素 [单选题]启用中的验讫章和其他业务用章由( )负责管理。
A.值班队（科）领导 B.值班组长 C.站勤务值班员 D.站值班领导 [单选题]下列哪种物质不是嘌呤核苷酸从头合成的直接原料( )
A.甘氨酸 B.天冬氨酸 C.谷氨酸 D.CO2 [单选题]夏季“四防”内容（ ）
A.防煤气中毒、防雷电、防暑、防小动物 B.防洪、防雷电、防倒塌、防暑降温。 C.防雨、防雷电、防暑降温、防中毒 [单选题]依据《石油天然气安全规程》AQ2012-2007,()是几乎所有工作人员长期暴露都不会产生不利影响的某种有毒物质在空气中的最大浓度｡
A.安全临界浓度 B.阈限值 C.危险临界浓度 D.8小时加权平均浓度 我来回答: 提交
|
