润滑系的基本功用和组成是什么?
参考答案:
润滑系的基本功用:润滑、冷却、密封及清洁摩擦表面。(2分)
润滑系的基本组成:包括机油集滤器、机油泵、限压阀、机油滤清器等。(3分)
关于C肽测定的描述正确的是()。
A.其与胰岛素呈等分子数分泌
B.反映胰岛B细胞功能
C.一定程度上反映胰岛素受体的功能
D.正常人葡萄糖负荷后,C肽值可增5倍或更多
E.可应用于经过胰岛素治疗病人的胰岛功能检查
The discovery of a new type of ceratopsian dinosaur suggests ceratopsians ______.
A.migrated to North America around 70 -- 80 million years ago
B.arrived in Asia from North America about 90 million years ago
C.originated in Asia and later migrated to North,America
D.could have moved to Asia from North America long ago