新世纪百货大楼“宝乐”牌童装平均每天可售出20件，每件盈利40元．为了迎接“六一”儿童节，商场决定采取适当的降价措施．经调査，如果每件童装降价1元，那么平均每天就可多售出2件．要想平均每天销售这种童装盈利1200元，则每件童装应降价多少元？设每件童装应降价x元，可列方程为____．

美国东部时间（西五区）2004年1月15日3时21分，美国宇航局向“勇气”号火星车发出了驶下登陆平台的指令，大约90分钟后，“勇气”号发回了已确认登陆火星的信号．该火星车的主要使命是寻找着陆区域是否存在过液态水的证据，这将有助于加深对地球以及地球上生命起源和进化等的认识．读下表中的相关数据，结合所学知识回答下题．

____ P+____O₂ $\frac{\underset{\_}{点燃}}{}$ ____P₂O₅

____ Fe₂O₃+____C $\frac{\underset{\_}{高温}}{}$ ____Fe+____CO₂

____ Fe₂O₃+____CO $\frac{\underset{\_}{高温}}{}$ ____Fe+____CO₂．

如图，菱形$OABC$的顶点$C$的坐标为$\left(3,4\right)$，顶点$A$在$x$轴的正半轴上．反比例函数$y=\frac{k}{x}\left(x>0\right)$的图象经过顶点$B$，则K的值为(     ) 
     

    Sometimes talent runs in families. Let's look at some famous (著名的) brothers and sisters.

    Andy Murray and Jamie Murray are very famous brothers. They are both professional (职业的) tennis players and they play in competitions all over the world. Jamie is older than Andy, but only by about a year. They look very similar. They are the same height and they have the same dark hair. Jamie became a professional player in 2004, one year before his younger brother Andy. But Andy wins more competitions than his brother!

    Kylie Minogue and Dannii Minogue are famous Australian sisters. Kylie began her career (事业) as an actress on Australian TV, then she began singing when she was 19 years old. She soon became famous all over the world. Dannii is younger than Kylie. She is also taller than her sister and she has darker hair. She began singing after Kylie, but she is also very famous. Dannii is also famous as a judge (评判员) on TV talent shows. Sometimes Kylie and Dannii sing together, and they sing really well.