Overslept!!

I had my part time job. However happening occered!! I overslept! I had to go the office at 6:00pm, but I woke up at 6:25pm. The class started at 6:20. I was late 5 minutes. My boss didn't angry. He has understandability. However, I was advised. I didn't want to be advised by him. So far, I was punctual! I wanted to my explanation to him. 66 words