permission

[Anonymous]

a. It was forbidden for the door to be opened.
b. It was not permitted for the door to be opened.
c. The door shouldn't be opened.

Are the above sentences correct?
I think that c is used normally about the present. Can it be used for the past, ie. as having the same meaning as a and b?

[Pete]

a. It was forbidden for the door to be opened.
b. It was not permitted for the door to be opened.
c. The door shouldn't be opened.

Are the above sentences correct?
I think that c is used normally about the present. Can it be used for the past, ie. as having the same meaning as a and b?
Sentences a and b are correct and refer to the past. As you suggest, sentence c would be understood to refer to the present unless there was a context that made it clear that the past was intended; then it would be correct and natural:
- He said that the door shouldn't be opened.
- The rule took effect every night at midnight: the door shouldn't be opened.