Translation of erarbeiten

I ran across the bridge to reach the other terminal and asked at the check in counter which connecting flights were still available. I wanted to avoid having to drive into the city at any cost.
I've been working on and off on the dictionary during the entire week, and I'll spend some more hours on it this coming weekend. Sometimes he would get a bit mixed up and use formal Castilian sometimes instead of informal.
I hope that we can teach each other a few things. I work as a nurse here in Boston, and it gives me a lot of joy and comfort because I like to help other people. It is a job that takes a lot of effort.