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    What picture do you have of the future? Will life in the future be better, worse or the same as now? What do you hope for about the future? Scientists think that life will probably be very different in 2050.

    First of all, it seems that people won't use TV channels by 2050. Instead, people will choose a program from a "menu" and a computer will send the program directly to the television.

    Water will become a very serious problem. We'll need much more water, but there won't be enough. Some scientists think that water would be the cause of war.

    Cars will run on new clean energy and they will go very fast. And there won't be any accidents with the help of computers. On the other hand, space planes will take people around the world in two hours.

   Robots will work in factories instead of people. Many factories have already used robots. Big companies prefer robots—they do not ask for money, and they work for 24 hours a day.

    In a word, by 2050, our life will change a lot and our future will be quite different from now.

若关于x的方程2x+a﹣4=0的解是x=﹣2，则a的值等于（　　）

打“120”急救电话时，必须要说明的是(    )

电动汽车的核心部件是超级锂电池。2016年7月，世界最大的电动汽车生产商——美国特斯拉在位于美国西部内华达州的首座超级电池工厂举行了揭幕仪式（如下图）。整座工厂占地面积为3200英亩，足足有107个足球场那么大。工厂2020年投产后，当满负荷生产时，超级电池工厂的员工将达到6500人，电池产量将达到2013年全球电池产量的总和。制造电池所需的钴、石墨等原料来自世界各地，生产技术来自日本。从原料到成品整个电池生产、电池回收过程将在一个工厂内完成，厂房顶全部铺设太阳能电池板。据此完成以下问题。