根据给出的汉语进行填空。

1. 1 have to _____the dog _____a walk(遛狗)and _____ _____ _____

(买东西)．

2. My grandfather had to get up at 5 a.m to _____ _____(劈柴) and_____ _____

_____(生火)

for the breakfast.

3. Then my grandfather had to_____  _____ _____(喂家畜)．

面向比特的同步控制(HDLC)协议的各种类型帧中，用于提供链路的建立、拆除及其他多种控制功能的帧为 (47) 。

A．信息帧

B．监视帧

C．无编号帧

D．控制帧