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.

分解因式：a²+3ab=____ 

美国正在实验助推火箭无损回收技术：火箭将飞船推送至一定高度；箭船分离，火箭停止喷火、落向地面；接近地面时，火箭再次消耗燃料、向下喷火，并以2m/s的速度匀速下降，如图所示．匀速下降时，火箭的动能 ____（变小/不变/变大），重力势能 ____ （变小/不变/变大）

​

hand    hat  ____