I was very tired because I did homework. It was difficult for me. It took 4 hours to finish it. I have to do more homework tomorrow.

I was very tired because I was doing my homework. It was difficult for me. It took me 4 hours to finish it. I have to do another homework tomorrow.

I was very tired because I did my homework. It was difficult for me. It took me 4 hours to finish it. I have to do another homework tomorrow.

I was very tired because I had done my homework. It was difficult for me. It took me 4 hours to finish it. I have to do another assignment tomorrow.