Everyone needs friends. But how do you find real friendship and keep it?

    The American writer ，Sally Seamans， tells young students some smart ways to find friends. Sally says founding friendship is just like planting a tree. You plant the seed (种子) and take care of it to make it grow.

    First, you should choose a friend. What makes a good friend? It is not because a person has money or good looks. A good friend should be kind and patient. ⑴For example, if you have a bad day, a good friend could listen to your complaints (抱怨) and do his or her best to help you. To make a friend, you can't be too shy. You should make each other happy and share your lives.

    But things can not always be happy. Even the best friends have fights. What should you do when you have a fight with your friend? You should talk to him or her carefully.

    ⑵Tell him or her how you are feeling, say what your friend did wrong and talk about why you did this or that. Remember that friendship is one of the most important things in your life.

根据短文内容，完成下列各题。

设函数$y=\sin 2x+\sqrt{3}\cos 2x$的最小正周期为T,最大值为A,则（     ）