题目

阅读下面短文，掌握其大意，然后从各小题所给的四个选项中选出最佳选项。Marcos was a hardworking farmer. Every day he asked his only son Paolo to___________ him in the fields, but Paolo seldom got out of bed before noon. Marcos was very sad about his only son.One evening Marcos’ old friend Luigi_________ , “Marcos, why aren't your fields ready for planting?” Marcos explained that he was old and his back hurt. He said that Paolo was___________ and did not help with the farming. “Marcos, you need to use your ___________ as much as your back. I have an idea f在盛少量氯水的试管中加入过量的溴化钾溶液，再加少量汽油，振荡静止后（   ）A．溶液为紫色B．汽油层呈橙色C．汽油层呈紫红色D．溶液为橙色