根据短文内容完成下列句子。 As an American,I was surprised to learn that Chinese students must be good at sports in order to get a top grade in PE class.  In the US, all you have to do to get an A in PE class is show up in proper gym clothes and look like you're trying. This is lucky for kids like me who aren't great at sports.  At my school, we had PE class twice a week. Every few weeks, we changed the activity we were doing. For a few weeks we played football. That was okay I was good at it.  But then we switched (转换) to baseball, and I was hopeless. I couldn't hit the ball at all! Luckily, under the American system, trying my best was enough. When I missed the ball, I knew it didn't matter. I'd still get a good grade. During the school year, we played many different sports, including American football, badminton, gymnastics (体操), tennis, golf, swimming and rock-climbing.  Every few months, we spent a few weeks in health class. Instead of going outside or to the gym, we sat in a classroom and learned about the human body and first aid (急救)． At PE classes, we learned a little, exercised a little, and had lots of fun. 1. The Chinese students must be good at sports in order to _______. 2. The writer is an American and is not _______ sports. 3. If you are  a  student in an American school, you are not good at sports but you still _______ . 4. During the American school year, the students have many different PE classes like _______. 5. The students in America can learn a little, _ ___ a little and had lots of fun at PE classes.