为了防止齿轮发生粘着、磨损，擦伤，烧结等损伤，（）是齿轮油极其重要的性能。
A.极压抗磨性
B.粘温性
C.防锈和抗腐性
D.抗泡性
参考答案：A
Scientists have many theories about how the universe_____.
A．came into being
B．was coming into being
C．had come into being
D．would come into being
下列关于纤维素性炎的描述中错误的是
A．常发生于浆膜、黏膜和肺
B．浆膜的纤维素性炎易导致浆膜粘连
C．心外膜的纤维素性炎常形成绒毛心
D．肺的纤维素性炎不会导致机化
E．常伴嗜中性粒细胞浸润
