孙中山在辞去临时大总统后，一度专注实业，为实现中国近代化而奔走。他在上海设立铁路公司，兼任铁路协会名誉会长等职，“俨然商界闻人”。他的这些活动反映出的本质问题是…（   ）

A．中国民族资本主义获得了较大幅度的发展

B．中国民族资产阶级具有发展民族工商业的热切希望

C．辛亥革命彻底扫除了发展资本主义的障碍

D．孙中山已成为中国民族资产阶级的杰出代表

One of the main responsibilities of ICMP is to report （1）. Although technology has produced increasingly reliable 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 concem ofIP JCMP wasdesigned, in part, to compensate for this shortcoming. Howerver, ICMP does not （3）errors, itsimply reports them. Error correction is left to the higher-level protocols. Error messages arealways sent to the original（4） because the only information available in the datagram aboutthe route is the source and destination 1P addresses. ICMP uses the source IP address to send theerror massage to the source of the （5）

（1）是（）

A.numbers

B.functions

C.strings

D.Errors