I put 'he sleeps after he drank' and it told me explicitly I need to put 'he has drunk'. Those two things are basically equivalent in this case, aren't they? (I'm an English speaker.) Is there a nuance of the Dutch that I'm not getting?
"He sleeps" in a general sense "after he has drunk" whenever he drinks/whenever he has drunk. This sentence doesn't work if you change it to "after he drank" because then the first part needs to be in the past too: "He slept after he drank".
bobjanova, the following are all correct:
he slept after he drank
he slept after he had drunk
he sleeps after he drinks
he sleeps after he has drunk
The first two sentences mean the same and are about the past. The second two sentences mean the same and are about the present.
The question here is which tense to use after the conjunction "after". In contemporary English, there is a distinct preference for using the present tense. However, in classic English (say up till 1900, and perhaps because of the influence of Latin), a perfect tense is often used after "after", in order to reinforce the time sequence: he does Y only after he has done X.
Whether Dutch would permit the present as well as the perfect in the DL sentence here I do not know. I suspect it would.
Your example seems awkward because you're mixing simple present with simple past in the same sentence. Simple present and present perfect go together much more naturally.
"Nadat" is a subordinating conjunction, used when connecting a subordinate clause to the main clause: "Nadat ik heb ontbijt gegeten, fiets ik naar werk." "After I have eaten breakfast, I bike to work."
"Na" is typically followed by a noun and is not used to separate clauses: "Na het ontbijt, heb ik naar mijn werk gefiets." "After breakfast, I biked to work."
The Dutch sentence you used: "Nadat ik heb ontbijt gegeten, fiets ik naar werk." isn't natural or even wrong. It should be: "Nadat ik heb ontbeten, fiets ik naar mijn/het werk". In the second sentence you should say: "Na het ontbijt ben ik naar mijn werk gefietst."
You can use the "report a problem" button in the bottom left (after you entered a sentence) to send missing alternative translations or to report other issues to the course builders.
If the second "hij" weren't here, would this sentence read (with na instead of "nadat", of course): Hij slaapt na te hebben gedronken (?)