Dr. Lee was one of my favorite professors in college. He was 1because of a trick he employed at the beginning of his first class. “I will put a2into each of my lectures. Your job is to try and3me in the Lie of the Day.”

    That was a 4way to focus our attention at the dry and 5subject---Capital Markets. On those days we actively6Dr. Lee's statements. Every once in a while, a lecture would end with 7seeing through the lie. Dr. Lee would say, “Ah ha! Each of you has a lie in your notes.8among yourselves what it might be, and I will tell you next Monday.”

    What made Dr. Lee's teaching 9smart was that there was no lie during the most technically10lecture. He offered the same challenge to11 our lecture notes. On the following Monday, he would hear our 12for almost ten minutes before he finally said, “Do you13the first lecture---how I said that every lecture

    Has a lie?”

    Tired from having our best theories shot down, we14.

    “Well, that was a lie. My previous lecture was completely true and15. But I am glad you reviewed your notes 16 this weekend. Moving on …”

    While my knowledge of the Capital Markets has17over time, the lessons hay stayed with me. “Experts” can be18and say things that sound right---so build a habit of 19new information and check it against things you already accept as 20.

（1）下列物质中：互为同素异形体的有　 ____　 （填序号，下同），属于同位素的有　 ____　，属于同一种物质的有　 ____　．

①液氯   ②$\stackrel{35}{17}$Cl  ③白磷   ④氯气   ⑤红磷   ⑥$\stackrel{37}{17}$Cl

（2）下列物质中：只存在共价键的是　 ____　（填序号，下同），只存在离子键的是　 ____　，既存在离子键又存在极性共价键的是　 ____　，既存在离子键又存在非极性共价键的是　____　．

①Ar   ②CO₂   ③Na₂O₂④KOH    ⑤MgBr₂    ⑥NH₄Cl    ⑦CaO   ⑧H₂SO₄

（3）某化学反应，设反应物总能量为E₁，生成物总能量为E₂，如果把化学反应中能量的变化看成是物质内部的能量与热能之间进行转变，则：

①若E₁＞E₂，则该反应为 ____热反应，该反应的过程可看成是“贮存”在物质内部的能量转化为 ____能而被释放出来的过程．

②若E₁＜E₂，则该反应为 ____热反应．该反应过程可看成是 ____的过程．

江南地区在汉代时“地广人稀、刀耕火种”，发展到宋代时出现了“苏湖熟，天下足”的景象。这一变化表明了经济领域中出现的现象是（    ）