"How long" 用英语表示为 "for how long" 或 "for how many (units of time)". 这是一个疑问词短语,用来询问某事已经持续了多长时间。
例如:
"How long have you been waiting for me?" (你等我多长时间了?) "For how long will the meeting be?" (会议多长时间?) "How long have you been learning Engpsh?" (你学英语多长时间了?)