Last week our school held a sports meeting. Everyone in our class felt very 1 because we 2 many matches. In the boys' relay race, Michael3 very fast and our class won the first place. Alice did well 4 the long jump and she also won. We're sorry that we did 5 in the high jump than other classes, but we're sure we could do better next time. I took part in the boys' 6 race. I did my best and was the first 7 the finish line. This encouraged 8 a lot. Now I love sports better and I think nothing makes me9 than taking exercise everyday and I believe some day I 10 able to be the best soccer player and take part in the Olympic Games.

小辉在纸叠的小船中加入适量的水，用酒精灯直接加热，纸船安然无恙，原因是（　　）