时下出现了一个新的消费群体——试客。这一群体在购物前先从网络上索取相关商家的免费试用品，经过仔细试用并与其他使用者相互交流后才决定是否购买。试客的购买行为（  ）

⑴Let me help you .____                           A、No , I can't .

⑵Are we all here today ?____                  B、No , thanks .

⑶Is that bag light ?____                           C、No , he isn't here .

⑷What day is it today ?____                    D、Certainly .

⑸Is it heavy ?____                                    E、No , it is heavy .

⑹Who's on duty today ?____                  F、I am .

⑺Can you carry it ?____                          G、Yes , it is .

⑻Could you help me , please ?____       H、OK .

⑼Thanks a lot .____                                 I、You're welcome .

⑽Let's put the books in the box .____    J、It's Tuesday .

①小楚将“今日事，今日毕”作为自己的座右铭

②小友痴迷武侠小说，甚至在上课的时候也偷看

③小华做事言出必行，对朋友有求必应

④小邹承认自己课堂上偷打游戏，并保证不再犯错

函数y=x²+x在x=1到x=1+△x之间的平均变化率为（　　）