（Ⅰ）解不等式①，得____；
（Ⅱ）解不等式②，得____；
（Ⅲ）把不等式①和②的阶级在数轴上表示出来；____
（Ⅳ）原不等式组的解集为____
In the future I am going to be an inventor．This winter holiday I don't want to go out to play．I want to ____something myself at home．I want to help old people____a light and folding bike．They ride it to the ____，then folding it and put it in the bag．After buying some things they can ride it and carry their things to go ____．They are not tired．I think if they see it，they must be very ____．
下列有关物质的性质或应用说法正确的是（ ）
与北方地区相比，南方地区农业生产的优势在于（ ）
