钢直尺示值的单位是（）。 ["mm（毫米）","m（米）","cm（厘米）"]
Which of the following statements represents the correct action to take when three crew members discover a fire?（） ["One man report the fire, and the other two men fight the fire","One man report the fire, one man fight the fire, and one man evacuate and secure the area","One man report the fire, one man fight the fire, and one man act as a safety observer","All three men fight the fire and report it immediately after it is extinguished"]
为什么说潘帕斯平原是阿根廷经济的心脏？
下列有关群落叙述中，正确的是：（） ["捕食作用必然提高群落的多样性","群落演替过程中总生产量\/总呼吸量（P\/R）始终大于1，到演替的顶级阶段P\/R接近或等于1","群落物种多样性随群落演替进展而增加，故顶级群落阶段，多样性最高","群落交错区中生物种类和种群密度会有所增加"]
闸刀开关文字符号为（） ["SA","SB","KA","KB"]
为什么巴西素有“咖啡王国”之称？第二次世界大战后它的经济发展有何特点？
