Expressing duration with "le"
Whether you need to express how long you lived somewhere, how long you studied astrophysics, or how long you worked as a mime, you'll need to use 了 (le) to express that time duration.
Saying how long you did something for in Chinese can seem tricky, as there is no preposition as in English. Instead it's all about word order:
Subj. + Verb + 了 + Duration + Obj.
So 了 (le) is placed after the verb (to indicate that the action is completed), followed by the duration. This is how you talk about the duration of completed actions.
- 他 学 了 一 年 中文 。He studied Chinese for a year.
- 我 看 了 一 个 晚上 书 。I read books all evening.
- 他 做 了 八 年 经理 。He worked as a manager for eight years.
Also note that 的 can be used in this pattern, which must be placed between the duration and the object.
Subj. + Verb + 了 + Duration + 的 + Obj.
- 我们 坐 了 十五 个 小时 的 飞机 。We took a fifteen hour flight.
- 奶奶 看 了 一 天 的 电视 。Grandma watched TV all day.
- 妈妈 洗 了 一 上午 的 衣服 。Mom washed clothes all morning.
To Express "Definitely Concluded"
Note that the previous pattern can be used to express the duration of completed actions which are no longer in progress, although strictly speaking, it's not entirely clear if the actions are still ongoing or not. To indicate that the actions are definitely concluded (not ongoing), a time word may be inserted into the sentence to indicate that you're talking about an event in the past:
Subj. + [Time Word] + Verb + 了 + Duration + Obj.
- 孩子们 周六 写 了 一天 的 作业 。The kids did their homework all day Saturday.
- 我 刚才 打 了 半 个 小时 电话 。I was on the phone for half an hour.
- 我 昨天 玩 了 一 晚上 游戏 。Yesterday, I played games all evening.
- 他 昨天 开 了 一 天 的 车 。He drove all day yesterday.
- 老板 今天 开 了 一 下午 的 会 。The boss had meetings all afternoon today.
To indicate that the action is definitely still in progress, use a slightly different pattern.