When the system upon which a transport entity is running fails and subsequently reatarts, the ___34___ information of all active connections is lost. The affected connections become half-open, as the side that did not fail does not yet realize the promble.

The still active side of a half-open connections using a ___35___ timer. This timermeasures the time transport machine will continue to await an ___36___ of a transmitted segment after the segment has been retransmitted the maximum number of times. When the timer ___37___, the transport entity assumes that either the other transport entity or the intervening network has failed. As a result, the timer closes the connection, and signals an abnormal close to the TS user.

In the event that a transport entity fails and quickly restart, half-open connections can be teminated more quickly by the use of the RST segment. The failed side returns an RST_i to every segment i that it receives. When the RST_i reaches the other side, it must be checked for validity dased on the ___38___ number i, as the RST could be in response to an old segment .If the reset is valid, the transport entity performs an abnormal termination.

34（）

A.data 

B.control 

C.signal 

D.state

历史上整个工业化过程中，约从18世纪初直至20世纪上半叶，经济结构变迁的主要特征乃是第二产业的兴起。关于历史上的这次巨变，比较准确的名称应该是“近代工业的兴起”在这一变革过程中（）

A.英国一花独秀始终充当先导

B.机械动力机器被广泛运用

C.工厂成为主要的生产组织形式

D.煤和石油同时成为新能源