If it seems odd that I have to help undergraduates - people who have all got into university - with their English, then read this story. Of course, these tests are for trainee teachers: I don't mean to imply that all schoolchildren are being taught by illiterates. But I do worry when I find basic errors in letters that come home from my son's school. I've lost count of the times I've seen "practice" and "practise" transposed, for instance.
Mind you, the most memorable error I can recall seeing was in maths rather than English. It was a homework assignment some years ago when Isaac was asked to make 18 pence out of three coins. He got extremely frustrated, and I couldn't blame him - it's mathematically impossible! Well, almost - as I took great delight in pointing out to his teacher, it can be done but only in old money - with three tanners or a shilling and two thrupenny bits - but I don't think that was what they had in mind!