（2015•滨州）下列运算：sin30°=$\frac{\sqrt{3}}{2}$，$\sqrt{8}$=2$\sqrt{2}$，π⁰=π，2^﹣2=﹣4，其中运算结果正确的个数为（　　）

    Looking back on the first twenty years of my life,I feel grateful to have been so healthy and happy.I'm happy because of many key factors（因素）.____

    Health comes first for me, because without health everything else is meaningless. Imagine starting a career without good health. Imagine achieving anything without good health.____

    Good health is not enough to be happy.____Money obviously pays for the basic necessities of life—food, housing, clothing, etc.—but it is also necessary for other reasons. Money guarantees(保证) we always get good medical treatment when we fall ill. Besides, we can also use money for entertainment that can add to our quality of life.

    Family is another important factor in having a happy life because it provides the love, joy, and support that everyone needs. I love my family with all my heart. I get pleasure from their pleasure. I suffer when they suffer.____ They give me advice when I have misunderstandings with my friends. More importantly, they are always there to share everything with me.

    ____ As long as I stay healthy, work hard to earn enough money and share both good times and bad times with my family,I will always be the happiest girl in the world.

A. Money is the most important factor which contributes to a happy life.

B. These three factors are all that I need and want in this world.

C. My family help me get through worries, pressures and difficulties.

D. We still need to have money in today's society.

E. Finally, I'm quite thankful that I am healthy, wealthy and happy.

F. Clearly, good health is much more important than any other things of one's life.

G. They include my physical health, healthy finances and my family's happiness.

经济发展水平居世界各大洲首位的是(     )

北宋程颐说道“唐有天下，如贞观、开元间，虽号治平，然亦有夷狄之风。三纲不正，无父子、君臣、夫妇，其原始于太宗也。故其后世子弟，皆不可使。玄宗才使肃宗，便篡。肃宗才使永王璘，便反。君不君，臣不臣，故藩镇不宾，权臣跋扈，陵夷有五代之乱。”作者意在说明（   ）