下面是小明同学在生活中的两个情景，请你运用所学知识，对其进行分析。

情景一：小明进入青春期后，心事不愿意和父母说，甚至和父母对着干，事后又往往觉得后悔。

情景二：在数学课堂上老师认为小华讲小话，点名批评了他，小华很不服气，和老师吵了起来。

“百善孝为先”。我国历来把“孝”看成是“天之经也，地之义也，民之行也”，因为孝敬父母是（    ）

①中华民族的传统美德           ②公民必须履行的义务

③社会主义的道德规范           ④为人做事的唯一准则

根据短文内容和所给单词提示，写出空白处各单词的正确形式。（每空一词）。

    Every society has ____ (it) special words, expressions and ways of saying things. One of the popular expressions in the United States is "Hitting the books". It ____ (mean) studying a subject with great effort(努力).

    One of the great challenges for students ____ (be) taking tests. Students spend long hours ____ (prepare) for a test. They read all their books carefully, and then read them ____ second time and a third time. They prepare for every possible question. They study every night. They are "hitting the books."

    In the United States, most children go to school ____ they are five years old. Public education is free and most children go to schools near their homes. School in these early years is fun. Children learn ____ (read) and write, but they also play games and go on trips. There is no reason at such an early age for them to hit the books.

    This situation changes as children become older. The subjects become ____ (difficult). Students must learn ____ world history, algebra(代数) and life sciences. Tests become more common.

    Pressure is growing to hit the books, study hard, and advance(升级). ____, most students only really begin hitting the books for long hours when they reach high school.

Knowledge is a prize that is not easy to gain.

（Ⅰ）求f（x）的解析式；

（Ⅱ）求f（x）的单调递增区间；

（Ⅲ）当x∈ $\frac{\pi }{12}$ ， $\frac{\pi }{2}$ 时，求f（x）的值域．