It is Sunday today but my three good friends are not at home. Tina is at the mall. Is she shopping? No, she isn't. She is eating lunch with one of her friends. Mike is still at school. Is he doing his homework? No, he isn’t. He's playing basketball with other boys. What about Lisa? Where is she? She is at the library. She is reading a book. Is it an interesting book? Yes, it is. Lisa likes this book very much.

一位美国历史学家在谈到一战前的欧洲形势时说：“欧洲变成一只火药桶，只等一粒火星将它引爆，”那么，成为“一粒火星”的事件是（   ）

除了水和无机盐之外，上表食谱中，含有的营养素主要有____、____等（写两种）；我认为小明列出的食谱中还缺少一种人体所必需的营养素____，“我的补充”是____（填写获取该营养素的一种食物名称）．