如图，双曲线y= (k≠0)上有一点A，过点A作AB⊥x轴于点B，△AOB的面积为2，则该双曲线的表达式为____.

    My town is a great place to live in. It's the best place to enjoy your free time. There are three movie theaters in the town. They are all good, but the one nearest my house is the best. Shopping is also easy. There are many shops and most of them are trendy. They sell very fashionable clothes. They are also cheaper than those in other cities, so students love to shop here. There are also a lot of video and music stores. These are very popular with students. I go to the music store every week to buy a new CD. The most crowded place for students to hang out is the park. Everyone goes there, so it's really interesting.

    Sometimes there are even street performers. Some students think they are boring, but I think they are the most creative people. I want to be a street performer, too.

下列物质不能用于鉴别氢氧化钠溶液和稀盐酸的是（　　）

辛亥革命的最后失败给中国人民留下的深刻教训是(        )
①帝国主义、封建主义是中国革命最主要、最凶恶的敌人②民族资产阶级没有力量领导中国民主革命取得胜利③革命要取得胜利必须发动和依靠群众④在半殖民地半封建社会的中国，走资本主义共和国的道路是行不通的