“惜秦皇汉武，略输文采，唐宗宋祖，稍逊风骚…”***在《沁园春•雪》中提及了中国古代多位杰出君王。其中“汉武”最主要的功绩是（　　）

查得资料：该牙膏摩擦剂由碳酸钙、氢氧化铝组成；牙膏中其它成分遇到盐酸时无气体生成。

I.摩擦剂中氢氧化铝的定性检验取适量牙膏样品，加水成分搅拌、过滤。（已知：氢氧化铝

 能溶解在氢氧化钠溶液中，生成NaAlO₂和水）

II.牙膏样品中碳酸钙的定量测定利用下图所示装置（图中夹持仪器略去）进行实验，充分反应后，测定C中生成的BaCO₃沉淀质量，以确定碳酸钙的质量分数。

依据实验过程回答下列问题：

    Do you want to know what our life will be like in the future? Let's have a look. You may get a surprise.

    You will go to the kitchen when you are hungry. You will give orders to the kitchen robot. The robot will cook the food for you in a few minutes. Then it will bring it to you.

    In the kitchen you will find a special food machine. The food machine will tell you what your body needs. It will help you eat healthily. The food machine will be connected with(连接) the kitchen robot. The robot can get messages from the food machine.

    After having a meal, you can go to your home office. You will work at home and you don't need to go out to work any more.

    You will have a special information screen. You can get any information on the screen. When you receive a message from a friend in America, your information screen will be turned on automatically(自动地).Your friend's face appears on the screen. Then you can talk to your friend easily.

清朝前期封建制度逐步衰落，但统一的多民族国家却得到了巩固。下列属于乾隆皇帝政绩的是（　　）