已知集合$M=\left\{y|y=x^2+1\right\}$,$N=\left\{y|x^2+y^2=1\right\}$,则$M\cap N=$(    )

    I'm Chinese ，but I am in England now. I can speak English. But I sometimes make mistakes with English. It was sunny yesterday. My class went to the park. I said，“Let's fly cats in the park. ”My classmates all laughed. I didn't know why. Then my teacher said，“Cats are animals. We can't fly them. But we can fly kites. ”“I know my mistake. I wanted to say kites，not cats. ”I said. Then we laughed again. That was funny.

    I have two good friends．They are Gina and Jenny, and they are twin(双胞胎之一的)sisters．They come from Singapore．They are 12 years old．They can speak English and Chinese．

    Now the twins are in China．Their family are in China，too．They live in Shanghai．There are five people in their family．They are their parents，their brother and them．Their mother is a doctor．Their father is a teacher．Their brother Alan is very young．He is four years old．He can't go to school．

    Gina，Jenny and I are in the same class．Every day, we walk to school and talk a lot．They say China is a very good place and they like China．

根据材料内容选择最佳答案。