A butterfly valve consists basically of a disc pivoted across the bore of a ring body having the same radial dimensions as the pipe in which it is fitted.According to the above sentence, which of the following statements is not true?（） ["The diameter of a disc is the same as the outer diameter of the pipe","We can infer that the valve is opened or closed by rotating the spindle","A butterfly valve comprises a disc and a ring body","The profile of the butterfly valve is a ring body"]
手电钻选用的电动机有（）。 ["单相串激电动机","三相工频鼠笼式异步电动机","单相电容式电动机","直流低压电动机"]
简述病状类型中的坏死局部植物细胞和组织的死亡。
在铁塔项目中下列关于开关电源模块的单个模块容量是（） ["30A","40A","50A","60A"]
更换低压闸门法兰垫子项目操作中，中毒的防范措施有：有限空间作业，必须检测有毒有害气体浓度，并由专人监护，做好个人防护。
选择养殖品种所需饲料的标准是什么？
