【判断题】The curved-shaft plough was a representative achievement of the renovation of agricultural tools in Han Dynasty.
【单选题】The horizontal component of force on a curved surface is equal to the
A.
(a) weight of liquid vertically above the curved surface
B.
(b) weight of liquid retained by the curved surface
C.
(c) product of pressure intensity at its centroid and area
D.
(d) force on a vertical projection of the curved surface
E.
(e) scalar sum of all elemental horizontal components
【单选题】实地研究方法是指不带有()而直接深入到社会生活中,采用观察、访谈等方法去收集基本信息或原始资料,然后依靠研究者本人的理解和抽象概括从第一手资料中得出一般性结论的方法。
【判断题】摇臂钻床在校夹或校正工件时,摇臂必须移离工件并升高,刹好车,必须用压板压紧或夹住工作物,以免回转甩出伤人。
【判断题】The curved-shaft plough was a representative achievement of the renovation of agricultural tools in Han Dynasty.
【单选题】下面对于问卷法收集资料的描述错误的是:
B.
根据问题的性质,答案一般可分采用两分制、四分制、五分制、七分制等形式分类并计分
【单选题】In Tang Dynasty, the skills of making ploughs had developed greatly. The most important improvement is that the_____________ replaced the long straight shaft.
【简答题】The________________ of the long-straight shaft into the short-curved shaft made it easier for the plough to make turns.
【单选题】()是指不带有理论假设而直接深入到社会生活中,采用观察、访谈等方法去收集基本信息或原始资料,然后依靠研究者本人的理解和抽象概括从第一手资料中得出一般性结论的方法。