阅读短文，判断正误，正确的在题前打T，错误的打F 
Helen is an English school girl. She’s eleven years old. Now she and her parents are in Jinan. Her parents teach English in our school. They are very kind. Helen is a good pupil. She’s good at maths. We are good friends. She’s clever and beautiful . Now she can speak a little Chinese.
(1)Helen is from America.   ____ 
(2)Her parents are English teachers____ 
(3)Helen is in Beijing now.____ 
(4)She isn’t good at maths.____
(5)She can speak a lot of Chinese.____ 

有理数－3的相反数（　　）

如果分式$\frac{1}{1-x}$有意义，那么x的取值范围是（  ）

下列铁的化合物中，铁元素的质量分数最高的是（   ）

①金刚石可用于切割玻璃，说明金刚石硬度大

②氢气、甲烷在点燃前要检验气体的纯度

③铝比铁具有更好的抗腐蚀性能，是因为铁比铝更活泼

④铁丝能在氧气中剧烈燃烧、火星四射，生成黑色固体

⑤洗涤剂具有乳化功能，常用来除去餐具上的油污

⑥二氧化硫、氮氧化物、一氧化碳和二氧化碳都是大气污染物．