你想把妈妈介绍给你的朋友，你可以说：
A．This is my mum.
B．She is my mum.
We need more trees.
A. plantB. to plantC. planting
听音，选出你所听到的单词。
（）（1）A . cleanB. cool C. keep D. car
（）（2）A . hot B. hotter C. get D. getting
（）（3）A .buildingB. changing C. singing D. interesting
（）（4）A .plant B. down C. becomeD. long
（）（5）A .spring B. air C. freshD. rice
Planting treesgood for us.
A. am B. isC. are
Trees can keep the air.
A. clean B. beautiful C. hot
I should my little sister.
A. take careB. look like
C. look after