You'd have to be sad to wear a shirt like that.
你穿着那样的衬衣显得老气。
I was very sad indeed to hear of your father's death.
听到令尊大人去世，我感到非常难过。
We are very sad to hear that you are leaving.
听说你要走了，我们十分难过。
Her moods kept changing ─ now happy, now sad.
她的`情绪总是变幻不定——时而欢喜，时而忧伤。
It is very sad when children feel unwanted.
小孩觉得没有人爱是很悲惨的。
You sad old man.
你这糟老头子。
The sad news cast a shadow over the proceedings.
这个坏消息给事件的进程蒙上了一层阴影。
The book is, by turns, funny and very sad.
这部书时而妙趣横生，时而悲悲戚戚。
We had some sad news yesterday.
昨天我们听到一些不幸的消息。