用所给词的适当形式填空。

1. My family _____ (decorate) our house before Christmas every year.

2. We _____ (celebrate) Christmas with a family meal.

3. I _____ (send) some Christmas E-card to my friends last year and I _____ (be) really happy to _____

    (make) a contribution to the environment protection.

4. People always _____ (sing) Traditional Christmas songs at Christmas.

5. My mother with my little sister usually _____ (go) shopping before Christmas.

6. My classmate, Xiao Ming, never _____ (go) to the parks on weekends. She just _____ (do)

    homework. She _____ (study) hard. But I _____ (not agree) with her. I _____ (think) she'd better

    _____ (have) a rest after hard work.

7. Mike _____ (not feel) well. He _____ (feel) sick, and his parents _____ (look) worried.

几十年来计算机网络的发展经历了（）阶段。

A.局域网

B.以单机为中心的通信系统

C.国际标准化的计算机网络

D.多个计算机互联的通信系统