Student or Learner
It has been eating dog foods for months.
it works great so far.
It has been a long time that I didn't speak English
I have been promoted to Associate Professor.
I have been doing this all the time.
I have been dancing since I was 8.
Are my sentences all correct? When should I use -ed after *have been*? Is there any possible that I have to use -en after *have been* ?