下图为人口迁移示意图，据此回答下面小题。

读一读，补全对话。

A. Have a cupof tea, Mum.   B. What can I do for Mum?

C. I love you,Mum!       D. Here's a card for you, Mum.

E. Here aresome flowers for you, Mum.

Bob: It's Mother'sDay. ____Ah! I have a goodidea. ____

 Mum: Thank you. I like these flowers.

 Bob: Happy Mother's Day!____

Mum: Thank you. It's a nice card.

 Bob: ____.

Mum: Thank you, my dear.

 Bob: ____

Mum: I love you too.

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 .

PM2.5是指大气中直径等于或小于2.5微米的颗粒物，也称为可入肺颗粒物。它可通过呼吸系统进入血液循环系统，对人体造成危害。请据图分析。