根据短文内容从方框中选择恰当的单词填空，使短文完整、通顺，有的需要变换形式。
lesson，subject，because，tired，I |
Hello，everyone!____ name is Li Hua．I am 13 years old．I've got six____ at school．And my favourite is maths．I have three____ in the morning and two in the afternoon．I am____ but I am very happy____ I can learn a lot．
C上的函数满足
，则
=