If we use the 'local' DTD:
<!DOCTYPE exam SYSTEM "ExamDTD">
<exam
xmlns:sr="http://brnl.ac.uk/strcs"
xmlns:csr="http://brnl.ac.uk/csrcns"
csr:course="cs203">
<sr:student>Fred Smith</sr:student>
<qapair>
<question>Who is the last King of England</question>
<answer>George VI</answer>
- - -
</qapair>
</exam>
