一般情况下,焊条电弧焊电弧电压在()之间。 ["200~250V","80~90V","360~400V","16~35V"]
下列关于软骨鱼和硬骨鱼的比较中,错误的是:() ["软骨鱼中动脉圆锥无收缩能力,硬骨鱼的动脉球可主动收缩","海生软骨鱼类的血液渗透压高于海水,海洋硬骨鱼体液浓度低于海水","软骨鱼和硬骨鱼都是体外受精","软骨鱼和硬骨鱼的呼吸器官都是鳃","软骨鱼有独立的肝脏和胰脏,部分硬骨鱼有肝胰脏"]
What is the proper first aid for LPG in the eye? () ["Apply an ice pack to the eye","Keep the eyelid closed","Flush the eye with plenty of water","Rub the eye area clea"]
鸟纲是陆生脊椎动物种类最多的一个类群,而鸟纲中种类最多的一个目是:() ["鹦形目","雀形目","隼形目","鸽形目"]
未经指定,任何机构不得从事列入目录产品的认证以及与认证有关的()活动。 ["检查","检测","检验","认证"]
“三皇五帝”正统的说法是指哪些人?