Translation:I still haven't finished my assignments.
I feel that "I haven't finished my homework yet" should also be correct.
should 我還沒有做完功課。 also, "I still haven't finished my homework" or "I still haven't finished my assignments" is better, since 還 represents the meaning of "still/yet" in thiis case.
完成 seems a little bit unnatural in this case... like you're completing some important procedure or task for bureaucratic purposes.
here you want to emphasize you are WORKING on your homework towards COMPLETION. so 做 is the verb associated with doiing homework, and 完 is a marker indicating completion.
It's way past a joke with this lesson.
It won't even take: "I have still not finished my assignment".
I think in all the course so far this is the worst lesson of the lot on several levels. It's obvious we are here to learn a course in very limited English, not Chinese.
I'm a university trained post grad, and English is my native language, but what is it like for someone to learn this course if they are not a native speaker?