请用相应序号正确表示相连化学符号中数字“2”的意义．

①CO₃^2﹣②2H₂③2Na⁺

混合动力汽车是一种新型汽车，它有两种动力系统．汽车加速，汽油机提供的动力不足时，蓄电池的电能转化为动能，使汽车加速更快；汽车减速，汽车动能转化为电能，由蓄电池贮存起来，减少能量的浪费．两种动力系统也可以独立工作，只有汽油机工作时，与一般的汽车相同；只使用电力时，由电动机提供动力．如表是国产某混合动力汽车蓄电池的铭牌，其中电池容量是蓄电池贮存的最大电能．该汽车匀速行驶时受到的阻力为720N．求：

电池容量	44kW•h
输入电压	220V
输入电流	20A
输出电压	150V

The following are some advertisements(广告). Read them and answer the questions.

No. 1   A big house with a big yard for a big family. There are four bedrooms, three bathrooms, a big living room and a great kitchen. The house costs $2,000 a month. Call Mrs. Morris at 4560987.

No. 2   Great location! A nice new flat building with a swimming pool. There is a big living room, a bedroom, a bathroom and a nice kitchen. It is $1,200 a month. The phone number is 7610201. You can ask Dana for help.

No. 3   There is a town house for you. The first floor is for playing games, and the second floor is for living. On the second floor, there is a living room, two bedrooms, two bathrooms and a nice big kitchen. There is also a great yard behind the house for children. It is $1,7000 a month. Please call Nathan at 4645 2436.

No. 4  Here is your new home! It is a big flat with three bedrooms, a living room, a dining room and a bathroom. The flat has a good parking place(停车位) but no yard. It is $1,600 a month. Call Wilson at 533 0202.

填填记记

____、____和____就是活化石。它们都是很久很久以前的物种，和它们同时期的物种大都____了，而它们却一代一代地活到了今天，十分珍贵。

国务院办公厅印发《关于发挥品牌引领作用推动供需结构升级的意见》提出，严厉打击侵犯知识产权和制造假冒伪劣商品行为；加强人才队伍建设，培养引进品牌管理专业人才。上述举措体现了（    ）

①人才强国是我国重大的发展战略

②维护市场秩序需要国家进行科学的宏观调控

③市场经济具有盲目性．滞后性的缺陷

④劳动力作为最活跃的因素，是生产力发展的重要标志