当具有5.0eV能量的光子照射到某金属表面后，从金属表面逸出的电子具有最大的初动能是1.5eV．为了使这种金属产生光电效应，入射光的最低能量为（   ）

党的十一届三中全会的召开使中国历史进入社会主义现代化建设的新时期，此“新”字的含义是（    ）

①党重新确立了实事求是的思想路线②党的工作重心由乡村转入城市，开始城市领导乡村的时期③党的工作重心转移到经济建设上来，实行改革开放的伟大决策④形成了以江泽民为核心的党中央领导集体⑤形成了以邓小平为核心的党中央领导集体

关于我国国情叙述错误的是（    ）

    What do you eat every day? Some people think about it. And some people will not make plans for their meals.

    Many people like to have fast food near their offices. This kind of food can make them fat and it is bad for their health. Even it will make them ill when they are old.

   What should a healthy person eat every day? Well, I will tell you the 'healthy eating habit(习惯)'. It comes from doctors.

     When people do a lot of work, the energy is burning(燃烧). So you need noodles, rice, milk, bread and eggs. If you don't eat them, you will feel tired. You should eat fruits and vegetables, too. There are a lot of vitamins（维生素） in them. They can make you strong. And they can give you water.