Expressing duration with 了 ("le")

表示动作从开始到现在（或某一时间点）已经持续了多长时间。常与动态助词“了”配合使用，构成“动词+了+时量+了”或“动词+了+时量”的结构。

Indicates the duration that an action has been ongoing from its start until now (or a certain point in time). Often used with the aspect particle '了', forming structures like 'Verb + 了 + duration + 了' or 'Verb + 了 + duration'.

用法：1. 强调动作持续到现在并可能继续：动词+了+时量+了（第二个“了”表示状态变化）。2. 仅表示动作完成的时长：动词+了+时量（无第二个“了”）。3. 否定式：没+动词+时量（不带“了”）。4. 疑问式：动词+了+多长时间+了？

Usage: 1. Emphasizes that the action has continued up to now and may continue: Verb + 了 + duration + 了 (the second '了' indicates a change of state). 2. Only expresses the duration of a completed action: Verb + 了 + duration (without the second '了'). 3. Negative form: 没 + Verb + duration (without '了'). 4. Interrogative form: Verb + 了 + how long + 了?