两种改法：
NEED 作情态动词时：You need not go with me unless you are free now.
NEED 作实义动词时：You don't need to go with me unless you are free now.上面的可以理解，下面理解有点不懂，可以讲解下子麽？谢谢！NEED 作实义动词，人作主语时，后接动词不定式，即to do 。实义动词作谓语的否定句是在动词前加don't / doesn't（ 一般现时），didn't(一般过去时)