why not 后面加动词原型。
例句
Why not make one by ourselves?
为什么不自己做一个呢？
Why not lie down for a while?
为什么不躺一会儿呢？
Why not give it up and turn in?
为什么不放弃它去睡觉呢？
So we thought, why not rabbits?
所以我们想，为什么不是兔子？
Why not buy them some gifts?
为什么不给他们买些礼物呢？
Why not listen to your feelings?
为何不倾听你自己的感受？
