阅读理解

　  Tim and Li Fang are not going to have any classes next week. They're going to work on a farm.

      They are going to leave at about seven thirty on Monday morning. They are going to travel to the farm by bus. They are going to wear old clothes because they are going to grow rice. They are going to have fish for lunch. They are also going to have a swim at the farm.

     Tim and Li Fang are excited about going to the farm. Not only are they going to help around the farm, but also they are going to learn about farming.

      Li Fang is worried that Tim won't arrive on time to catch the bus because he is nearly always late. Li Fang often has to say to him, “Don't be late, Tim. ”

①是公民参与政治生活的重要平台

②有利于党和政府科学决策和民主决策

③是公民参与管理国家和社会的基础和标志

④有利于保证人民的知情权、表达权、监督权

化学是建立在实验基础上的学科．关于下列各实验装置的叙述中，不正确的是（　　）

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