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.
- 妈妈 看 了 一 天 电视。Mom watched TV all day.
- 他 在 Google 做 了 八 年 经理。 He worked as a manager at Google for eight years.
- 我们 坐 了 十五 个 小时 飞机 去 美国。We took a fifteen hour flight to the United States.
To express "definitely completed"
Note that the pattern before 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 completed, 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.
- 昨天 他 写 了 一 天 作业。 He did his homework all day yesterday.
- 我 刚才 打 了 半 个 小时 电话。 I was on the phone for half an hour.
- 他 今天 喝 了 一 个 晚上 酒。 He drank alcohol all night.
- 我 昨天 玩 了 一 个 下午 游戏。Yesterday, I played games all afternoon.
- 上 个 周末 我 和 老公 开 了 三 个 小时 车 回 老家。Last weekend, my husband and I drove three hours to our hometown.
To indicate that the action is definitely still in progress, use a slightly different pattern.