One ofthe main resposibilities of ICMP is to report(1).Although technology has produced increasingly relaible transmission media, errors still exist and must be handled. IP is an (2) protocol. This means that error checking and error control are not a concern of IP. ICMP was designed, in part, to compensate for this shortcoming. Howerver, ICMP does not (3) errors, it simply report them. Error correction is left to the higher-level potocols. Error messages are always sent to the original (4) because the only information available in the datagram about the route is the source and destination IP addresses. ICMP use the source IP address to sent the error massage to the source of the (5).

空白（2）处应选择（）

A.reliable

B.unreliable

C.available

D.unavailable

男性患者，36岁，近2个月反复出现脐周疼痛伴腹胀、发热、盗汗，偶有腹泻或便秘。查体：体温37.3℃，轻度贫血貌，腹平坦，有柔韧感，右下腹和脐周有压痛，无反跳痛和肌紧张，肝脾肋下未触及，移动性浊音阴性 腹部超声显示回盲部增厚，腹腔有纤维分隔，包裹性积液。

最可能的诊断是

A．结核性腹膜炎

B．肠结核

C．腹膜间皮瘤

D．肠系膜钙化

E．腹腔脓肿