阅读理解,根据短文内容,判断下列句子正误。
Today is my birthday. After school, I came back home and found balloons hanging(悬挂) in my room and a big cake on the table. I'm sure(确信) it's mum's work. My mother is a doctor. I invited(邀请) three friends to my birthday party. They came with their lovely presents: a dictionary, a doll and a kite.
16. The balloons were hanging in my mother's room. ( )
17. A big cake is on the table. ( )
18. I invited three friends to my birthday party. ( )
19. My mother is a teacher. ( )