DS1 is in yr 10.He gets a learning review every 6 weeks with target grades for end of the year and currently. His targets are all Bs. First report says everything apart from music are currently grade D! 
Now that is fairly poor but DS tells me that most students are way off their targets atm. OK, fair enough I guess - only 6 weeks into yr 10. But the latest one that we had last night is worse! He had gone backwards in 3 subjects, and up in only 2. His levels for attitude and behaviour are all good or outstanding. So I guess that makes him just plain thick 
What really confuses me is that DS said his last English test was one mark of a B - either he's lying or that hasn't shown up in the grade as yet.
DS can't tell me what the problem is - he is struggling with maths, he admits that, but doesn't know why science (which used to be his favourite subject) is so low.
I am feeling pretty desperate now. He's never been great in school - but held his own - and most of his school reports were along the lines of 'OK but could do better' but this seems really serious. And it's going to get more so. And it seems he is trying reasonably hard.
DH reckons we should make an appointment to see his tutor next term but I don't know what difference it will make. So disheartened.