Look at this. It’s a blue bag. It is my bag. What’s in it? Look, this is my English book. It’s blue, too. My Chinese book is also in my bag. It is yellow. This is my pencil case. It’s big and nice. I like English and Chinese. My bag is my good friend.

根据短文内容选择最佳答案。

小题1: My bag is       .

A．yellow

B．blue

C．nice

D．big小题2: --- What’s in my bag? 

---        .

A．My English book

B．My Chinese book

C．My pencil case

D．All the three小题3:My Chinese book is also in my bag. "Also" means（意思是）      .

A．也

B．颜色

C．不在

D．放进小题4: My       is my good friend.

A．Chinese book

B．English book

C．pencil case

D．bag

二叉树的中序遍历序列为DBEAC，前序遍历序列为ABDEC，试画出这棵二叉树，并写出二叉树的后序遍历和层次遍历序列。