补全对话。
A．It's so big!
B．It's on the first floor．
C．No，it isn't．
D．Twenty．
E．Yes，we do．
（2015•临沂）“保护环境，人人有责”，为了了解某市的空气质量情况，某校环保兴趣小组，随机抽取了2014年内该市若干天的空气质量情况作为样本进行统计，绘制了如图所示的条形统计图和扇形统计图（部分信息未给出）．
请你根据图中提供的信息，解答下列问题：
45÷9＝____
Many students know what they want to be in the future* . We think boys are different from girls. Here is a survey in Green High School. Let's look at the diagram* .
一束光线与平面镜的夹角为60°，那么反射角为 ____，光线经过平面镜反射后，传播方向改变了 ____
