当北半球大部分地区正午太阳升得最高，白昼时间最长，黑夜时间最短的一天是（）

阅读下面这首宋词，完成后面各题。

醉落魄·离京口作

苏轼

轻云微月，二更酒醒船初发。孤城回望苍烟合。记得歌时，不记归时节。

巾偏扇坠藤床滑，觉来幽梦无人说。此生飘荡何时歇？家在西南，常作东南别。

2009年10月4日，温家宝总理访问朝鲜，并向中国人民志愿军烈士陵园敬献了花圈。缅怀先烈，回忆历史，当年的朝鲜战争对中国产生的影响主要有
①抗美援朝巨额的军费开支，加重了中国经济的负担
②美国第七舰队开到台湾海峡，使台湾问题直到今天还悬而未决
③打击了美帝国主义的侵略政策和战争政策，极大地提高了我国的国际威望
④保卫了中朝两国的独立与安全，为我国的社会主义改造和建设赢得了一个相对和平的环境

阅读材料，完成任务。

    My uncle Jack is an interesting man. When he speaks, his mustache（胡子） always dances. It is so funny. He wears glasses and a funny hat.

    I don't like my boss（老板） at all. He is heavy with two small eyes. I think his glasses are too small for him.

— Look, the salesman（商人） is coming.

— Which one?

— The one with short black hair. He always takes his umbrella(雨伞) and suitcase(旅行箱). And his tie is very ugly.

— What are you doing, Lucy? Look at your pants. They are so dirty!

— I am doing some cleaning. Don't come here, Jane. Your beautiful skirt will be dirty.

维持人体生命活动所需的热量，主要哪种能量直接转化而来（）