题干

央视《是真的吗?》节目中,主持人做了“电池+口香糖锡纸=取火工具”的实验:取口香糖锡纸,剪成条状,将锡纸条带锡面的一端接在电池的正极,另一端接在电池的负极,很快发现纸条中间处开始冒烟,起火苗,如图所示.这是因为锡纸是____(选填“导体”或“绝缘体”),将它的两端直接接入电池正负极,就会造成____,迅速产生大量的热量,使温度达到锡纸的燃点而使之燃烧,锡纸中间剪成凹形,是为了增大此处的____(选填“电流”或“电阻”),使实验更易成功.

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答案(点此获取答案解析)

导体,短路,电阻

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阅读短文,从每题所给选项中选出可以填入空白处的最佳选项。

    Once there lived a poor family in our town. They were so poor that there was almost(几乎)1 in the house but a pot(罐) 2 a broken table. In it there was a little rice. They 3the rice from their neighbour for the coming New Year. On New Year's Eve(除夕夜), the wife already fell asleep, but the husband was 4 in bed, worrying about their life. Suddenly he heard someone breaking into the room.

    “It must be a thief(小偷),” he thought, “5 it doesn't matter. The thief can steal(偷) nothing.”He didn't shout or move. But he kept6over the thief.

    The thief came into the house and was only7 in the rice under the table.

    “But8can I take it away?” the thief thought hard. Then he had an idea. He9 his coat, put it on the ground between the bed and the table and turned around to take the 10 .

    Now the husband knew11the thief would do. He picked up the coat quickly and covered himself with it12the thief turned back.

    The thief took the pot, and poured(倒) the rice onto the coat. Then he began to feel it. But he was13 to find that his coat was gone.

    “Hey,” he shouted out. The14 woke up the wife. She asked her husband, “Did you hear any sound? Maybe there is a thief in the room.”

    “Shut up! (闭嘴)” replied her husband, “15 to sleep. There is no thief in the room.”

    “That's impossible,”the thief shouted loudly, “If there isn't a thief, then, where is my coat?”