Each machine supporting TCP has a TCP transport entity, either a library procedure, a user process, or part of the kernel. In all case, it manages TCP streams and （） to the IP layer.A TCP （） accepts user data streams from local process, breaks them into pieces not exceeding 64KB, and sends each piece as a separate IP （） . When datagrams containing TCP data arrive at a machine, they are given to the TCP entity,which reconstructs the original byte streams. The IP layer gives no guarantee that datagrams will be delivered properly, so it is up to TCP to time out and （） them as need be. Datagrams do arrive may well do so in the wrong order, it is also up to TCP to （） them into messages in the proper sequence.

A TCP （） accepts user data streams from local process.

A．connection

B．file

C．entity

D．destination

关于分泌性中耳炎，叙述错误的是（）

A.是以鼓室积液和传导性耳聋为主要特征的中耳非化脓性炎性疾病

B.中耳积液性质可为浆液性漏出液或渗出液，也可以是黏液

C.中耳积液严重时，中耳压力增大可产生剧烈耳痛

D.中耳积液严重时可出现感音神经性聋

E.患儿如一耳患病、对侧听力正常，可长期不被发觉