公安机关保卫国家安全与维护社会治安秩序的任务，主要是通过( )实现的。A．公安专业

After completing and signing it, please return the form to us in the envelope      ________.[ ]

A. providing 

B. provided

C. having provided 

D. provide

同义句转换

1. She spent 20 yuan on the dictionary. 

    She ________ 20 yuan for the dictionary.

2. Peter does well in Chinese.

    Peter ________ ________ ________ Chinese.

3. The old man has been dead for 10 years.

    It's 10 years ________ the old man ________.

4. Does Mary like dancing?Can you tell me?

    Can you tell me ________ Mary ________ dancing?

5. How much is it?

    What's the ________ of it?

预定义技术的主要通信工具是定义报告。报告形式有多种，下列哪一种可以表明外部实体、过程和文件之间的数据流动

A．叙述文字

B．流程图

C．逻辑判定表

D．数据字典

建筑砂浆按所用胶凝材料的不同，可分为（）。

A.水泥砂桨

B.石灰砂浆

C.砌筑砂浆

D.抹面砂浆

E.水泥石灰混合砂浆

大三巴牌坊是一处怎样的景点