在“调查公园的生物”活动中，你认为哪位同学的做法是正确的（　　）

英国革命中出现了克伦威尔任护国主的军事独裁统治，法国大革命后出现了拿破仑称帝。这主要是由于（     ）

著名科学家居里夫人首先发现某些原子具有放射性，即原子能自动地放射出一些固定的粒子，一种元素的原子经过放射变成了另一种元素的原子。据此可知，放射出来的粒子可能是（  ）

   American school life is different from (和……不同) Chinese. American students usually get to school at around 8:30 in the morning. They put their school bags in their lockers (柜子) and only take one book, one notebook and one pen to each class. In class, American students can sit in their seats (座位) when (当……时候) they answer their teachers questions
   At around 12:00 students have lunch. American students don’t go home for lunch. They have it at school. Most students like pizza(比萨), hot dogs or hamburgers. At 1:00 in the afternoon, they start to have classes. Their classes are usually over(结束) at three o’clock. Then they join in the activities （活动）of clubs or sports.