لا أعرف بَعْد-I don't know yet: Correct but pay attention to (بَعْد) because it has sokon on the letter ع.  ربما أذهب إلى المغرب-I might go to Morocco: Correct.  I still haven't taken a shower: It's either you say: (لم أقم بالاستحمام بعد), or (لم أستحم بعد).  I saw you the other day: You can say (رأيتكَ ذلك اليوم) for a male, and (رأيتكِ ذلك اليوم) for a female.  تستطيعين أن تعيدينه ثانيا؟: I'm not sure if you want to translate this or you are just asking us to rewrite the sentences for you :) but here's a correction for it: If you are speaking to a female: هل تستطيعين إعادته ثانية؟ if you are speaking to a male: هل تستطيع إعادته ثانية؟

لا أعرف بَعْد-I don't know yet correct, but it could be لا أعلم بعْد depending on the context.  ربما أذهب إلى المغرب-I might go to Morocco correct, but this sounds more like "perhaps/maybe I'll go..." If you want "might go" it's better to use قَدْ أذهب إلى المغرب  I still haven't taken a shower- لا يزال أخذت دش لم أسْتَحِمّ بَعْد because زالت, لا أزال isn't used with negative verbs like "haven't" رأيتك يوم الآخر-I saw you the other day hmmm "the other day" doesn't really translate literally into Arabic but you can say ذاك اليوم as in "that day" or منذ يومين as is "a couple days ago" تستطيعين أن تعيدينه ثانيا ؟ تعيديه ثانيةً (you take out the ن from تعيدينه because it's منصوب by أن)