【单选题】According to the extent of fermentation, tea is usually divided into three basic types: ___________, oolong tea and black tea.
【单选题】The major difference between oolong tea and black tea is
A.
the oxidizing degree of tea polyphenol
B.
the change in moisture
D.
the extent of metals content
【单选题】有关曲轴的安装,下面说法正确的是( )。
C.
在轴承的内、外两个表面上都抹发动机油,然后安装
【判断题】在应用动能定理解题时,非理想约束的约束力要做功,可视为主动力计算。