Translation:He swims fast and runs slow.
他游泳游的很快 this sentence is like "He swims, (swim) very fast. 游泳，跑步 are seperable verbs. You need to duplicate the main verb again （which are 游，跑 here） before describe how the subject do it. So you may say 我游得很快。or 我“游泳”游的很快。You may watch this video for further information. https://www.youtube.com/watch?v=ggPbyZN96ss Start from 8:40
Thanks for the link. Very useful. They explain even the sentence "游泳游得很快" :)
Bad English here. "He swims very fast; he runs very slowly" should also be accepted.
They apparently accept this answer is you replace "slowly" with "slow".
The adverb "slow" do exist, however, it appears it is mainly used in the US. Duolingo seems to adopt American English.
https://dictionary.cambridge.org/dictionary/english/slow mainly us: He drives too slow!
American English is losing its adverbs (in a descriptive sense), but they're still prescribed. I would mark this wrong if a student gave it to me. Why that dictionary has added it at the bottom is a mystery - it's really not standard (American) English, though it does reflect common usage in some dialects.
"He swims very fast; runs very slow." Better than the "correct" translation, but still marked as wrong.
The second clause in your sentence is missing a subject, so your answer is technically bad English.
You either need to repeat the subject or replace the semicolon with the word "and".
If duolingo throws this in their lesson, they should put "separable verbs" on the page linked by clicking on the light bulb... it's confusing to beginners.
If you're going to respond entirely in Chinese, please make sure you're using the correct characters. You have some errors, and it makes it so that anyone who needs to look up anything you wrote probably won't be able to figure out what you mean. 叫 is "to call." 教 is "to teach." I haven't heard this grammatical construction related to time spent doing something myself, but I have heard this construction in something like 我游不泳了, which means "I can't swim." I'm not proficient with that construction, though, so I would normally say this differently. Whether you can use it or not depends on whether or not the second word in the verb is really a verb or a noun independently. I don't know if it can actually be used with 游泳 or not.
Didn't Einstein say that moving clocks ran slow? Not relevant but I had to write it.
Always abstract things we have to face to without any explanation. I have so many caracters just to indicate the degree of an action, it's so useless and cumbersome.
This sentence requires an adverb in English - slowly, not slow. There is no option to report the English.
I was confused by this too. Check out this link. It should provide some guidance. Look under "The common usages of separable words" , specifically section 3.
The link provided above by Michaelingua (https://www.digmandarin.com/chinese-separable-words.html) is very helpful.
Fast and slow are incorrect (although frequently seen) English here. Should be "quickly" and "slowly".
What is the dé 得 for? It says it means "need", but it's not what they put at all...
Either watch the video in the first post, or this is very helpful too, explains it all: https://resources.allsetlearning.com/chinese/grammar/Degree_complement#Degree_Complements_with_Objects.