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    It matters a lot if you don't have your breakfast. In the United States, recently a test ____ (perform) by the scientists. People ____different ages from 15 to 80 were included in the test. They were offered all sorts of breakfasts, but sometimes they didn't get any breakfast. How ____ (good) their bodies worked was seen when they had eaten breakfasts. At last, the scientists got the results ____ (show) that the persons who ate breakfasts worked better. This fact appears ____(be) especially true for the persons working with brains. It was commonly believed that not having breakfast was____way of losing weight. Opposite to____ many people think, you may become so ____ (hunger) that you eat much for lunch, in ____case, you are gaining weight. Therefore, you may lose more weight if you reduce your other ____ (meal).

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has been performed,of,well,showing,to be,a,what,hungry,which,meals

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    电热膜是一种新型的电热器件,如图甲所示是一种常见的电热膜.电热膜是在绝缘的聚酯薄膜表面,经过特殊工艺加工形成的一条条薄的导电墨线,导电墨线两端与金属导线相连,形成网状结构,其内部结构如图乙所示.

    电热膜通电工作时没有发红、炽热现象产生,它与被加热物体直接接触,产生的热量很快传给被加热物体,所以电热膜本身温度并不太高,不易氧化,使用寿命长.在制造电热膜时,会出现不同区域导电墨线厚度不均匀的现象,厚的导电墨线电阻小.导电墨线电阻随温度变化的关系如图丙所示,这种温度特性的优点是,它不会因厚度不均匀而出现严重发热不均、局部过热的现象,这是电热丝所不具备的,它保证了电热膜各处的温度均匀.

(1)电热膜取暖器工作时,室内空气温度升高是通过____ 方式增加空气内能的;

(2)某根导电墨线的局部导电材料脱落,如图丁中A部分,这根导电墨线的电阻____ ;

A.变大     B.变小     C.不变     D.以上三种情况均有可能

(3)与传统的电热丝加热器相比,电热膜取暖器的发热效率高,原因是____ 

(4)将图戊中一块电热膜接入电路,正常工作时金属导线中A、B处电流分别为IA和IB,则IA____ IB;(填“<”、“=”或“>”)

(5)电热膜不会因厚度不均而出现局部过热的现象,原因是____