今年是中国人民政治协商会议会议成立68周年。有人认为:人民政协就是一个由民主党派和无党派人士参加的与***的地位平等的爱国统一战线组织，这句话对吗，请谈谈你的认识？

李时珍写《本草纲目》用了27年，达尔文写《物种起源》用了27年，马克思写《资本论》用了40年。这一切说明(　　)

如图所示为氢原子的能级结构示意图，一群氢原子处于n=3的激发态，在向较低能级跃迁的过程中向外辐射出光子，用这些光子照射逸出功为2.49eV的金属钠，下列说法不正确的是（   ）

下列物质能够反应，且没有明显现象的是(    )

    There is a park near my house. It's very big and beautiful. It's fine today. I am in the park now. There is a book shop on my left. Some people are reading books. On my right, there is a long river. There are many flowers and trees near the river. There are some boats on the river. Some children are rowing boats. There is a hill in the park. I'm going to climb the hill. I like the park very much.