mad
单词辨析：
指精神错乱的，或行为不理智的、失控的。
They realized that the captured spy had gone mad.
他们意识到那名被俘的间谍已经疯了。
The cartoon figure was depicted as a mad scientist.
这个卡通人物被刻画成了一名疯子科学家。
You must be mad to say that!
你那么说简直是疯了！
People all went mad with joy.
人们全都欣喜若狂。
指精神失常或不理智的，常可与 mad 换用。
He feels so alone that he sometimes wonders if he's going crazy/mad.
他觉得非常孤单，有时候他怀疑自己是否快要发疯了。
A crazy/mad old woman lived in that room.
一个疯老太婆住在那个房间里。
表示患精神病时，mad 与 crazy 均含冒犯之意，通常用 mentally ill 来代替。
指因极度焦虑或恐惧而情绪失控的。
His mother hasn't been able to reach him on his cellphone and is getting frantic.
他母亲一直打不通他的电话，急得快要发疯了。
She was frantic with worry.
她担心得要命。
指因极端不安、担心、激动等而行为或情绪失控的。
hysterical screams
歇斯底里的尖叫
She became hysterical and began crying.
她变得歇斯底里，开始大哭起来。
He became almost hysterical when he heard the news.
他听到这个消息时几乎要发疯了。
相关例句：
He's mad about you
他很迷恋你。
He was weight training like mad.
他在拼命地进行负重训练。
The audience went mad.
观众们十分狂热。
Why does he want to do a mad thing like that? It's not like him.
他为什么要做这样的傻事呢？这可一点都不像他。
So you're not mad keen on science then?
那么你对科学并不是太感兴趣了？
I'm pretty mad about it, I can tell you.
告诉你，我对这件事感到非常恼火。