- except (except for) = apart from
'We work every day except Sunday.'
'Everyone was there except (for)/apart from Tom, who was ill.'
- unless = except if = if ... not
'You can't go in unless you are a member.'
= 'You can't go in except if you are a member.'
= 'You can't go in if you are not a member.'
= 'You can go in only if you are a member.'