The most violent tornado have winds of more than 400 kiolmetres a minute
问题描述：
The most violent tornado have winds of more than 400 kiolmetres a minute
其中tornado是不是单数形式 如是为什么后面用have而不是has
答
tornado英[tɔ:'neidəu] 美[tɔ:'neidəu]
n.旋风,龙卷风
n.旋风,龙卷风
复 数：tornadoes,tornados
因此你的句子,应该有误,要么是The most violent tornados have winds of more than 400 kiolmetres a minute.
要么是The most violent tornado has winds of more than 400 kiolmetres a minute.