多长时间多久一次
how often is───多久一次
how long for───要多久
how long does───多长时间
how long to───还要多久
how long you───你多久了
for how long───要多久
goodhow long───好多久
how───n.(How)人名；(英)豪；adv.如何；多少；多么；conj.如何；n.方法；方式
how do you often───你经常做什么
Who talked to the child, how long, how often, how many different words were said and how many total words were said. How many past-tense verbs and in what circumstances.───谁跟小孩交谈，多久，多频繁，用了多少不同的字词，总共使用的词汇是多少，使用多少过去时态的动词，是用在什么语境下使用。
This configuration provides a balance between how often the garbage collector runs and how long it takes the garbage collector to collect garbage.───此配置在垃圾回收器运行的频率和垃圾回收器进行垃圾回收操作的时间长度之间进行了平衡。
However, it is worth noting that converting the information concerning how often failures occur and how long they last into an "availability" figure averages out the failure information.───然而，将关于失效发生多频繁和它们持续多长时间的信息转换成一个“可用性”特征是没有价值的。