《专利法》规定,发明专利权的期限为()年,实用新型专利权和外观设计专利权的期限为()年,均自()起计算。
参考答案:20;10;申请日
People appreciate________with him because he has a good sense of humor.[ ]
A. to work
B. to have worked
C. working
D. having worked
脑栓塞最常见的病因是( )。
A.糖尿病 B.动脉粥样硬化 C.风湿性心瓣膜病 D.高血压和动脉粥样硬化E.高脂血症