I am not a native speaker and I am experiencing an issue with the word still. I have some sentences here:
a. He is still a good friend.
b. He is still be a good friend.
c. He is still busy.
d. He is still be busy.
e. Japanese is still being taught in schools.
f. Japanese is still be taught in schools.
g. Japanese is still taught in schools.
I guess I know what the above sentences should be without still, but I have no notion why there is a be after still in (b), (d) and (f) despite the fact that I have been googling all day and have found nothing. I now even doubt whether what I know so far is right or not, so I raise some questions:
Are all seven sentences above grammatically right? Why?
If the answer to 1 is yes, what the difference among them, especially the versions with and without be?
If no, how do I correct them?