甲肝的主要传播途径是() ["粪口途径","空气传播","虫媒传播","接触传播","性传播"]
名山旅游地空间竞争的特点() ["可替代性竞争","非替代性竞争","可利用性竞争","非利用性竞争"]
肾移植术后病人死亡的主要原因是()。 ["切口出血/血肿","急性排斥反应","感染","消化道出血","外伤挤压易肾挫伤"]
人体每日需要的盐量为() ["2.5g","3.0g","4.5g","6.0g","5.5g"]
GB/T232-1988规定,当材料厚度大于25mm时,应将冷弯试样厚度加工成25mm,其宽度应加工成()。 ["25mm","50mm","30mm"]
温度对加氢精制过程的影响?