题目

氯酸钾制氧气的化学方程式书写正确的是 A．2KClO32KCl+3O2                  B．2KClO32KCl+O2↑ C．2KClO32KCl+3O2↑                    D．2KClO32KCl+3O2↑                                                                                                                                                              Once there was a boy in New York. His name is Sam. He started painting at the age of four, and when he was five, he was already very good at it. He painted many beautiful pictures, and a lot of people bought his pictures.Sam’s pictures were different from other people’s ，because he never painted on all of paper. He painted on half of it, and the other half was always empty.“That’s very clever,” everybody said, “No other painters have ever done that!” One day somebody asked him,” Please tell me this, Sam .Why do you paint on the bottom（底部） half of your pictures , but not on the top half ?”“Because I’m short,” Sam said, “and my brushes can’t reach very high.”1.Which country did Sam live in ?_____________2.Was Sam good at painting when he was five?_________3.What did Sam do with his pictures?_________________4.Were Sam’s pictures the same as others’?______________5.Why didn’t Sam paint on all of the paper?_____________