I am a s____ of Park School. I am from A____. I am now living in a big c____. I live near school. I go to school on f____. It takes me only ten m____. I live far away from the library. I get t____ by bus. It takes me a____ half an hour. I live far away from City Park. I get there by u____. It takes me about t____ minutes. I go to school e____ every morning. Then I do some cleaning in the classroom. I f____ classes at about half past three in the a____. Then I walk h____.
①CO、O2（2：1）②NH3、O2（8：1）③NO2、O2（4：1）④N2、H2（1：3）
