How did we define the common sense?

in my understanding, the common sense is not only the skill to deal with people and daily life, but also the skill how to think the problem and work on it in your school and work.

I took a class in the school in US. We used C language to write programs for our projects. there was a chinese lady in my class. The instructor always sighed with feeling and said that she had common sense for the computer language in the class. how come her algorithms were always clever? But she was the last one to find a job among us. She was very shy. I turned in her resume to my boss and mentioned about how sharp she is when I began to work. She passed two people’s phone-screen interview and failed with on-site interview. I was curious about her on-site interview, but I could not ask around since I was new. I have talked to my boss why she failed when I have worked there for a quite time. My boss said that she did not look like confident even though she answered all of technical questions. They were not happy with her answers when they asked how she taken care of children if she needed to go to work when they had lunch with her. My boss said that she did not have common sense and is not easy to work with. I told my boss that it was his loss. He smiled and told me it is too early to say so.

You have to have common sense when you like to climb up higher in either management or technical ladder.