Hello UsingEnglish.com,

I been looking up for two words that I don't haven't listed in my books. The first one is back on. I heard a sentence like "Is your credit back on", first of all, what does it mean? and for what other examples can I used it?, can you give me an example?. The word is a reduction form of "Back on track" or "Back on your feet"

The second word is left off, I heard sentences like "When we left off in the last class/relationship" and the same question, what does it mean?, for what other examples can I use it?, can you give me an example?.

Thanks in advanced,
Antonio.