Carol and Susan are very good friends. They are in the s     1    class at school and they often visit each other's h    2    at weekends (周末). Now they are   b    3    eight years old. Carol's mother has got a new baby.

Carol is very  g    4    to have a little sister. So she is always talking about her to Susan. At first she is very i    5    in the new baby because she doesn't have any brothers or sisters. But after some time she begins to get tired of Carol's endless talking (喋喋不休地谈论) about it. She a     6    feels a little jealous (嫉妒) of her friend. 

One morning when the two girls m    7    in the school ground, Carol says to Susan, " Sue,Do you k    8     my baby sister has put on nearly half a pound in weight (体重增加了半磅) this week." 

"That is not very   much." answers Susan. "I know a baby a    9    he puts on ten pounds a day."

"Oh, that can't be t    10    ." answers Carol laughingly. "Whose baby is it?" "An elephant's" says Susan.