英语翻译为什么用needn't而不用don't need,

needn't don't need needn't与don't need don't need,needn't 的区别 don't need to 和needn't don't need 等不等于 needn't needn't to come,don't need come,don't need coming与needn't co 为什么用you needn't wake him up,而不用you needn't to wake him up. need的否定形式什么时候该用needn't什么时候该用don't need needn't与don't need的区别 We ________much sleep.(don't need,needn't) needn't 和 don't need to 有什么不同? don't need 和needn't 有什么区别啊?