A：How was your last Sunday，Sam?

B：____ I really had a good time.

A：____

B：I played pingpong with my father.What about you?

A：____

B：Oh.You're really hardworking！ ____

A：Yes，of course.I saw a film with my cousin on Sunday night.

B：Really？ ____

A：Yes.It was about dinosaurs.It was very interesting.

下列各式：﹣x+1，π+3，9＞2，$\frac{x-y}{x+y}$，s=$\frac{1}{2}$ab，其中代数式的个数是（　　）

下列属于侵犯消费者对商品和服务的自主选择权的是    （   ）
①电信局规定所有安装电话的用户必须在该局购买电话机   ②某饭店用死鱼冒充活鱼让顾客食用
③某厂通过虚假广告夸大其增高鞋垫的功效                     ④某学校规定学生必须在学校食堂就餐

如图，在平行四边形ABCD中，对角线AC、BD相交于点O．如果BD=12，AC=10，BC=m，那么m的取值范围是（　　）