“疯狂”的星球

金星是太阳系中八大行星之一，中国古代称之为长庚、启明、太白金星。金星地表大气压约是地球的90倍，大气成分主要由二氧化碳组成，约占96%，因此它的地表具有强烈的温室效应，在近赤道的低地，温度可高达500°C。

在高度50至70公里的金星上空，悬浮着浓密的厚云，把大气分割为上下两层。你知道吗？地球云层的主要成分是水（水的液滴），而金星云层的主要成分是硫酸（硫酸的液滴），其中还掺杂着硫的粒子，所以呈现黄色。H₂SO₄的生成主要源于太阳光中波长短于160nm的紫外光对CO₂的光解，使其变为CO和原子氧，原子氧非常活泼，能与SO₂反应变为SO₃，SO₃与水反应变为H₂SO₄，在金星，下的雨真是名副其实的酸雨。金星里，H₂SO₄的形成过程是不断循环的，H₂SO₄从大气较高较冷的区域降至较低较热的区域，当温度达到300℃时，H₂SO₄开始分解为SO₃和水，SO₃再分解为SO₂和原子氧，原子氧接着与CO反应变为CO₂。SO₂与水会上升到上层，重新反应又释放出H₂SO₄。

依据文章内容，回答下列问题。

人体内葡萄糖被小肠吸收进入血液后，到达脑部所经历的途径是（   ）

①上腔静脉②下腔静脉③主动脉④肺动脉⑤心脏⑥肺静脉⑦肺部毛细血管⑧各级动脉．

    My friend Tony is an American 1. He is ten years old. He lives2 his family in China now. There are 3  people in his family; his mother Mrs. Green, his father Mr. Green and his little sister Amy. He has a white cat. 4 name is Betty. Look！Amy is playing 5Betty. His father, Mr. Green, is watc­hing TV. His mother is doing housework. What about Tony? He is doing 6 Chinese homework. He can't 7Chinese well, but he likes Chinese very much. Tony's 8 works in a TV station. His father works in a school as an 9 teacher. Tony and his sister 10 to the same school.

$\sqrt{m-n}$的一个有理化因式是（　　）