He has never behaved so violently before. ==> He is behaving.....
He is behaving more violently than before.
I have been to fewer countries than you have. ==> I haven't ......
I haven’t been to as many countries as you have.
The film was less interesting than I had expected. ==> The film .....
The film was more boring than I had expected./ The film was not as interesting as I had expected.