"We swim for half an hour every day."
Duolingo is correct. 游泳 is a separable verb. This is a complicated subject. It's best to refer to Chinese Grammar Wiki at https://resources.allsetlearning.com/chinese/grammar/Separable_verb or other sources.
Thanks for the link, but note how it starts. (I paraphrase for brevity, clarity, and emphasis.)
Level: B1, far beyond Duolingo's 15 levels.
Separable verbs (离合词, líhécí) get their name from their ability to "separate" into two parts, verb + object, with other words in between. In fact, you could also simply call separable verbs "verb-object phrases."
Now, I recall Duolingo introducing them as verb+noun, but what we have here is an "object" that we English speakers tend to categorize as "verbs," ignoring gerunds and other
nouning verbs techniques.
Last week, I downloaded Hanping, which glosses 泳 both ways, noun first:
- to swim
P.S. English inherited its separable verbs from German trennbare Verben.
I had always assumed that the grammatical rule was "[动][时间]的[名]", that is to say that you could only split verbs composed of a first character which is itself a verb, and the rest which is a noun.
- 我拉了一个晚上的肚子 (this one was an excuse I heard a native give to our teacher for being late in class :-p)
Here, 泳 is itself a verb, but not a noun, so this sounds unnatural to me. However as I've never been actually taught this grammatical rule I'm concerned that I might actually be wrong?
It is a separable verb
Duolingo is only considering this structure correct:
Subject + time + verb in the action + time (duration) + object in the action
Let's call this structure 1. But there is other structure that is correct as well and it was considered wrong for me, which I think it should not happen.
Subject + time + action + verb in the action + time (duration)
In this structure (2) if a 离合词 (separable word) is being used, the verb must be repeated, otherwise it is considered a grammar mistake. I already saw a question (sentence provided in Mandarin to be translated to Mandain) where the verb is not repeated, which is a mistake.
Note: subject and time can swap positions. Time is option depending on what the speaker wants to express. This applies bor both structures.
What do I mean with action, verb in the action and object in the action? These are all references for 离合词 (separable words)
E.g.: Action: 游泳，跑步，踢足球 Verb in the action: 游，跑，足 Object in the action: 泳，步，足球
I think that duolingo should introduce both structures and name both like structure 1 and 2. Then point out wich one the user should use, so no one relies just on one of these structures, because both are commonly used.
This is just a suggestion and I hope it helps all the users to be more clear about this grammar.
That is the verb 遊 yoú, meaning "to swim". It is the first part of the separable verb 遊泳 also meaning "to swim". The second part 泳 comes after the duration 半个小时的 describing the first part.