阅读理解（每题3分，共15分）
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 years old. They study at QingLan Primary School. Mary likes English, Jane likes math and May likes music.They all study hard. 
根据短文内容，判断句子正误。对的打“√”，错的打“×”。
(    ) （1）There are 3 children in the story.
(    ) （2）Mary is shorter than May.
(    ) （3）Mary is heavier than Jane.
(    ) （4）Jane is the youngest.
(    ) （5）They are all good friends.