一、根据中文意思，完成句子或对话。
1. 天空为什么是蓝色的？
the sky ?
2. 你看上去如此累。为什么不休息呢？
You look so . have a rest?
3. 你为什么不喝一杯茶？
you have a of tea?
4. ——你为什么如此高兴？
——因为今天是我的生日。
— you so ?
— today is my birthday.
5. 他为什么如此伤心？
he so sad?

一、1. Why is，blue
2. tired，Why don't you
3. Why don't，cup
4. Why are，happy，Because
5. Why is

二、按要求完成句子。
1. We can't eat too many snacks because they are bad for us.(对画线部分提问)
you eat too many snacks?
2. They can't get on the bus because the bus is full.(对画线部分提问)
get on the bus?
3. Why don't you go to bed now?(改为同义句)
go to bed now?

二、1. Why can't
2. Why can't they
3. Why not