下边漫画给我们的启示是（     ）

制作一个圆锥模型，已知圆锥底面圆的半径为3.5cm，侧面母线长为6cm，则此圆锥侧面展开图的扇形圆心角为____ 度．

阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

    This story took place in 1903. Adam, an American businessman, was carried out to sea by a strong wind. A ship ____ (spot) and rescued him, ____  was how he got to London by accident. He at once went to the American embassy ____ (ask) for help, but was refused. Two rich gentlemen invited him home because of a bet. They asked Adam a few questions, and Adam responded ____ a polite manner. They gave him a letter and asked him not to open it until two pm. Adam left wondering ____ would happen to him.

下列关于“叶绿体中色素的提取和分离”实验的叙述，不正确的是 （  ）