how long
英 [haʊ lɒŋ] 美 [haʊ lɔːŋ]
conj.多长时间
例句：
1.How long have they been at war?
他们交战有多长时间了?
2.How long have you been colouring your hair?
你染发有多长时间了?
3.How long have you been in your present job?
你干现在这工作多长时间了?
4.How long have you been living in this country?
你在这个国家居住多久啦?
