阅读短文，判断下面句子的正误。

    Mary, Jane and May are very good friends. Mary is shorter than May. May is heavier than Jane. Jane is thinner than Mary. How old are they? Mary is 7 years old. Jane is 12 years old. And May is 9. They study at Wuhan Primary School. Mary likes English. Jane likes maths and May likes music. They all study hard.