①发现并保持对学习的兴趣 ②掌握科学的学习方法 ③养成良好的学习习惯 ④投入“题海战术”
A:①②④
B:①②③
C:①③④
D:②③④
—Yes. And they teach _________.
化简分式:2x+2÷x-6x2-4
There are animals in the zoo.