一旦超过法律规定的有效期限，知识产权权利就自行消失，是指知识产权的（）

A.专有性

B.时间性

C.地域性

D.无形性

E.永久性

Each fire hose coupling on a ship must have threads that meet the specifications of the（）.

A.American Petroleum Institute

B.National Standard Firehose Coupling

C.American Society of Mechanical Engineers

D.Underwriter's Laboratories，Inc