Sorry that I maybe misinterpreting what you were trying to say. When you say 'exercise' do you mean mock exams or assignments? Answering the question about how the real exam differs from
ExamLab, the most important thing to mention is the real exam is not that tough as ExamLab. ExamLab questions are made in a way that 'practices' you to figure out the tricky parts, so you can easily spot them in any significance of the real exam. We have an
article on ExamLab that describes why ExamLab questions are made in that way and the best way to achieve the optimal advantage of practicing with ExamLab questions.
Devaka