I'd like to ______ David ______ the new chairperson of the students' Union. [ ]

A. recommend, as

B. realize, for

C. remind, of

D. remember, to

传输层的主要任务是向用户提供可靠的______服务，透明地传送。

A．端-端

B．节点-节点

C．节点-端

D．分组