将下列自然现象与相应所属的动物行为连接起来。
金龟子遇敌假死____               a繁殖行为
雌鸟衔虫喂养雏鸟____            b防御行为
大雁的迁飞____                      c社群行为
饿狗为食物而争斗____            d攻击行为
蚂蚁间的分工合作____            e节律行为

    It's Sunday afternoon. The weather is fine. There is a football match between class 2 and class 4. Many students are watching. They're excited. Now, Zhang Wei has the ball. He passes it to Wei Kun. But Wei Kun can't kick the ball. Then John has the ball. The ball flies to Zhang Wei's arm. Zhang Wei is very angry. The ball files into the goal. How is Zhang Wei feeling? He is so happy! Class 4 won the game. Class 2 is very sad.

过点M（2，1）作曲线C：$\left\{\begin{array}{c}x=4\cos \theta \\ y=4\sin \theta \end{array}\right.$（θ为参数）的弦，使M为弦的中点，则此弦所在直线的方程为（　　）

He _______ an English club last year and has improved his English a lot.