These days, many students like playing 3D games. Do you know what 3D games are like? In most 3D games, game players need to control (控制) a character. The character can be a robot or a soldier (士兵). Game players usually use the mouse to make the character move around in his own world. Game players can find things such as food and weapons (武器) to help them go on with the game. The character can go straight, sit down, turn left, turn right or pick up things in the game.
    Some 3D games have many levels (等级). The character needs to finish different goals for each level.Game players can play against their computers, and sometimes they can play with other players on-line. It's great fun to play 3D games. But playing 3D games for long is not good for our study.

某种药品的说明书上，贴有如图所示的标签，一次服用这种药品的剂量范围是（　　）

下列各函数①y=$\frac{k}{x}$；②y=$\frac{k^2+1}{x}$；③y=$\frac{3}{5x}$；④y=$\frac{4}{x+1}$；⑤y=$\frac{1}{2}$x；⑥y=$\frac{1}{x}$﹣3；⑦y=$\frac{4}{x^2}$和⑧y=3x^﹣1中，是y关于x的反比例函数的有：____（填序号）．

定义在（0，+∞）上的函数f（x）满足下面三个条件：

①对任意正数a，b，都有f（a）+f（b）=f（ab）；

②当x＞1时，f（x）＜0；

③f（2）=﹣1

（I）求f（1）和 $f\left(\frac{1}{4}\right)$ 的值；

（II）试用单调性定义证明：函数f（x）在（0，+∞）上是减函数；

（III）求满足f（log₄x）＞2的x的取值集合．

大家认为，今年以来在复杂严峻的国际国内环境下，中国经济能够实现稳中向好，实属不易。面对复杂形势，不搞短期刺激，统筹当前长远，创新宏观调控方式收到积极成效。从生活与哲学角度看，上述成就的取得主要是因为（   ）

①尊重规律、按规律办事②充分发挥主观能动性，突破规律制约③把尊重规律与发挥主观能动性相结合④充分发挥社会主义国家集中力量办大事的优势