语法填空

    July is coming. People all around the world are talking about their ____ (vacation). Parents would like ____ (help) their children relax. ____ (luck), they have two months off. Some people enjoy quiet life, so many of ____ (they) stay at home watching TV, using computers and so on. ____ some spend time differently. My pen pal Tony ____ blonde hair is a boy from the US. He says that ____ (America) like going to the countryside. Just like his big family, they often go to a farm. There, some can feed animals, some can play and ____ (other) can watch ____ nice sky and rivers. They can also taste delicious food. They are quite ____  (interest) in the life there.

①1⊗3=2；

②方程x⊗1=0的根为：x₁=﹣2，x₂=1；

③不等式组 $\{\begin{array}{c}\left(-2\right)\otimes x-4<0\\ 1\otimes x-3<0\end{array}$ 的解集为：﹣1＜x＜4；

④点（ $\frac{1}{2}$ ， $\frac{5}{2}$ ）在函数y=x⊗（﹣1）的图象上．

其中正确的是（   ）

如图的图形面积由以下哪个公式表示（　　）