苷元-O-（2，6-去氧糖）x为（）
A.Ⅰ型强心苷
B.Ⅱ型强心苷
C.Ⅲ型强心苷
D.次级强心苷
E.强心苷元
参考答案：D
From his _______expression, we can guess that the problem maybe was quite _______.
A．puzzled ; puzzling
B．puzzling; puzzled
C．puzzled; puzzled
D．puzzling; puzzling
总装配图不是制造零件的直接依据，不必注出每个零件的（），只标注与部件的装配、安装、运输、使用等有关尺寸。
A、局部尺寸
B、全部尺寸
C、技术要求
D、公差要求
