"He could not sleep at her place."
Translation:Er könne nicht bei ihr schlafen.
I'll give it a go but I'm sure a German could do better With können it is often better to use "to be able" version of the verb rather than can.
Konnte is past tense so "er konnte das machen" can translate to "he was able to do that"
"Er könne nicht bei ihr schlafen." means either "[he said], he is unable to sleep at her house" ie reported speech sentence or "[If she invited him to stay over,] he would not be able to sleep at her place" ie conditional sentence
But I have to say this form of the subjunctive (called Subjunctive 1) is very rarely used for a conditional sentence and think that it normally only used for formal writing and almost never in spoken german.
I really don't like this Duolingo sentence because it uses a concept which is difficult for German learners and has many subtleties without making the context clear.
It gave me "He could not sleep at her place" to translate and I tried "Er konnte nicht bei ihr zu Hause schlafen."
The correct answer was "Er konnte nicht bei ihr schlafen."
Why don't we use any word to designate her place? Otherwise it sounds more like "He could not sleep with her" which doesn't seem correct, translation-wise. Can anyone shed light on this?
This is also grammatically correct. Where nicht goes makes a very subtle difference but is usually unimportant. (i'll use the non subjunctive in the examples)
"Er kann nicht bei ihr schlafen" "he is not able to sleep at her house"
"Er kann bei ihr nicht schlafen" "it is sleep that he is unable to do at her house"
so the first sentence implies - he can sleep somewhere but not at her house.
The second sentence suggests - he can lay on the sofa under a blanket, but could he fall asleep? no.
If unsure I try to put nicht just before the verbs at the end of the sentence.
Here "bei" is used in something of a fixed expression. No need for "Haus." Bei + Rosemarie = "at Rosemarie's (house)." So "They were eating dinner at Rosemarie's" = Sie haben Abendessen bei Rosemarie gegessen.
Now replace Rosemarie with the personal pronoun "her" ("bei" takes dative, so you need 'ihr"). = Sie haben Abendessen bei ihr gegessen.
"ihres" is the wrong form of the personal pronoun for her. You need dative, not genetive. If you did want to go ahead and literally say "her house," you would still need the dative/neuter form of "her" because of "bei": = Sie haben Abendessen bei ihrem Haus.