对.用last for也可以,但一般last for后跟具体时间.如果无具体时间,一般只用last如,How long will the fine weather last?好天气能延续多久?She felt sure that their friendship would last.她确信他们的友谊会日久...如果还原成陈述句不是 it will last for how long么？如果这样的话前者不是错了么？换成陈述句的话就是it will last how long..it will last two days,,这样用可以么可以。last a few days和last for a few days意思是一样的