63－18____45           77－19____60           67＋17____85

37____45－20           23____33－9                    16____30－16

35－20____36 －21         58－19____72－33

已知互不相等的实数a,b,c成等差数列,c,a,b成等比数列,且$a+3b+c=10$,则a=(   )

    My name is Mary. I am seven. Ted is my brother (兄弟). He's twelve. We are in the same (相同的) school. My mother is a teacher. She teaches (教) English. She is a teacher in our school. My father is a doctor (医生). He works (工作) in a big hospital (医院). I have a dog. Its (它的) name is Bell (贝尔). We are good friends.

根据短文选择合适的答案。