July 4 is the birthday of the United States of America. Since 1776, people have 1 the Independence Day holiday every year.
   What do people 2on Independence Day? Many colorful and interesting things. They have fireworks shows in the evenings and sing songs. Some families organize picnics with barbecues (烧烤). Kids can3much delicious food like hotdogs.
   And these parties are a good time to dress up. Some kids make July 4 hats 4 the stars and stripes(星条) of the country's flag on them. And Independence Day is in summer. Many kids use stars and stripes fans to keep themselves 5 .
   It's a great day, but no one forgets that it's6too. US people are proud of their   7  and proud of what the founders did for it. On Independence Day everyone gets the chance to show it.

改革开放是实现中华民族伟大复兴的关键招，是当代中国发展进步的活力之源，是坚持和发展中国特色社会主义的必由之路。

材料一：混合所有制是社会主义初级阶段基本经济制度的重要实现形式。我国经济发展进入新常态，迫切需要将发展动力转换到创新驱动上，深入推进国有企业混合所有制改革，不仅有利于提高国有企业的持续创新能力，而且有利于带动各类非公有制企业特别是民营企业加大研发投入、加快创新步伐，进而放大各自优势，实现良性发展、互促共进。

材料二：2017年5月23日下午召开的中央全面深化改革领导小组第三十五次会议强调指出，试点是重要改革任务，更是重要改革方法。要认真谋划深入抓好各项改革试点，坚持解放思想、实事求是，鼓励探索、大胆实践，敢想敢干、敢闯敢试，多出可复制可推广的经验做法，带动面上改革。

通常情况下，下列物体属于导体的是（     ）