马的黑色与棕色是一对相对性状，现有黑色马与棕色马交配的不同组合及结果如下：

①黑×棕→1匹黑  ②黑×黑→2匹黑  ③棕×棕→3匹棕   ④黑×棕→1匹黑+1匹棕

根据上面的结果，下列说法正确的是（　　）

新中国成立以来，社会主义建设取得辉煌成就。请完成下列空白。

阅读下面材料，为G20杭州峰会拟一副对联。总字数不超过20个字。

    主题为“构建创新、活动、联动，包容的世界经济”的二十国集团领导人峰会于2016年9月在中国杭州拉开帷幕。钱塘江边，西湖之畔，各国领导人齐聚杭州，为世界经济把好脉、开好方。***主席在开幕式上发表主旨演讲，用“四个建设”“三个共同”为全球经济提出中国方案，提供中国智慧，提振了全球经济增长的信心和勇气，推动本次峰会取得丰硕成果。

       American schools begin in September after a long summer holiday. There're two terms in a school year. The first term is from September to January, and the second term is from February to June. Most American children begin to go to school when they're five years old. Most students are seventeen or eighteen years old when they finish high school.
      High school students take only five or six subjects each term. They usually go to the same classes every day, and they have homework for every class. After class, they do a lot of interesting things.
     After high school, many students go to college(大学). They usually have to pay a lot of money. So, many college students work after class to get money for their studies.