函数f（x）=x2-4x，x∈[0，a]的值域是[-4，0]，则a的取值范围为_
题型：填空题
问题：
函数f（x）=x2-4x，x∈[0，a]的值域是[-4，0]，则a的取值范围为______．
题型：填空题
阅读理解。
My name is Li Fei. I'm in Class 6, Grade 6. I have three good friends. Their names are Qian Feng, Da Bao
and Tian Tian. I always go to school on foot because my home is near the school. But Qian Feng's home is far
from school. He goes to school by bus. Da Bao always goes to school by bike. Tian Tian often goes to school
on foot.
Today is Sunday. We don't go to school. We go to the park together. We're very happy.
1. 根据短文内容，看看以下小朋友是怎样去学校的，用线连起来。
2. 回答下面的问题。
Do they go to school on Sunday?
_____________________________________________________________