下列四图属于北半球的是（ ）
A：
B：
C：
D：
通过下列实验得出的结论，其中正确的是（ ）
①既可说明甲烷具有可燃性，又说明了甲烷是由氢元素和碳元素组成
②既可说明二氧化碳的密度比空气大，又说明了二氧化碳不能燃烧也不支持燃烧
③既可说明水是由氢元素、氧元素组成，又说明了水分子中氢原子和氧原子个数之比
④既可探究可燃物的燃烧条件，又说明了白磷的着火点比红磷低
⑤既可说明二氧化碳易溶于水，又说明了二氧化碳具有酸性．
根据短文内容和所给汉语提示，写出短文空白处各单词的正确形式。每空限填一词。 At school many things happen to us. We may feel ____ （激动的）when we succeed in a school play. We may feel sorry if we lose an important ____ （比赛）. We want to keep the memory in our lives. How to keep memories? Our teacher, Mr. Smith, has taught us how to ____ （记住）things to make our own yearbook. A yearbook is a____ （种） of book which is used to memory wonderful moments. It’s usually made at the end of year. Last ____ （十二月）, we began to make our yearbook.____(首先) we chose the persons that had done something ____ （特殊的）, then some ____ （学生） interviewed them, some ____ （写）down their stories, others took photos of them. Finally our teacher helped us to put the things____ （一起）. Then we had our first yearbook.
