Liz had been bleeding for a long time! She was my closest professional colleague and good friend at the time when we worked in an IT company. It was her first day back at work after an operation and I thought she should have taken a few more days to recover. Realizing that we couldn't stop the bleeding, we headed to the emergency room and spent hours there waiting to be seen. After the treatment, I drove her to my apartment. I had to leave her in my apartment while I dashed off to take a final exam for a very important course I was taking. Upon my return, we decided Liz was in a good enough condition to sustain a trip back from my Northern Virginia apartment to her home in Maryland. Although it was nearly midnight and we were both exhausted, we still decided to set off. Unfortunately, in a not particularly safe part of town, we heard my car make a strange noise, and then ti was shaking violently as we drove along. Quickly, I stopped the car in the road and found a tire had blown out. Not knowing how to change a tire and feeling scared, I was trying out to figure out what to do next. Liz, weak from losing all that blood all day and weighing only about eighty pounds to begin with, came out and tried to help me. I had to scream at her to get back in the car and relax. Within seconds, a taxi pulled up behind us. A huge man appeared and began walking toward us. I felt that the blood drained out of my face and I nearly fainted in fear. "Got a flat tire, girls?" he asked. "Yes," I answered in a trembling voice. In no time at all, the man changed the tire for us and rushed off back to his taxi. He refused any payment and did not even tell me his name. He would never know how badly we needed his services that particular evening. And I, with a grateful heart, will never forget his kindness. The author thought that Liz was bleeding because  _  .
she worked too hard in an IT company she had an operation but didn't rest enough she hurt herself in the workplace carelessly she had a long trip from her house to the company