命题“$\forall x\in R,x^2\ge 0$”的否定为 (     )

下列关于化学发展的看法错误的是（　　）

2014年4月24日，美国总统奥巴马访日，提出规定钓鱼岛及其附属岛屿是《日美安保条约》第五条适用对象，并支持右翼政府修改宪法。中国外交部重申，不管美国如何搅局，日本右翼如何挑衅，都不能改变钓鱼岛是中国固有领土这一铁证如山的事实，也无法动摇中国政府和人民捍卫领土主权的意志和决心。对此认识正确的是（）
①公民要自觉履行维护国家统一的义务
②美国这一行为违背了当今时代的主题
③领土主权关系我国的核心利益，神圣不可侵犯
④当前国际竞争的实质是经济和科技力量的较量 

    Jim Davis is an American cartoonist. He is1as the creator of the successful comic strip Garfield.

    Jim David was born on July 28, 1945. He grew up on a small farm with his parents, his brother and 25 cats. As a2child. David spent lots of time in bed. With his pencil, paper and imagination，he3pictures. Then he discovered that the pictures were more interesting with words. After college, David4his cartoon career. He noticed that there were many comic strips about dogs, but few about5. though the .world was full of cat lovers. He combined his knowledge with his6of the 25 cats he grew up with , then Garfield was created. The fat lazy cat soon became7as soon as the comic strip were published. It8in more than 2,600 newspapers worldwide now.

While devoting his life to taking care of the cat, David took part in many activities for public. He9environmental protection and wild life protection. He also-has lots of10, such as golf, fishing，chess，sandwiches，and spending time with his son, James.