Some courses, for example the Dangerous Goods D Endorsement course, have modules that unlock once you have finished the core modules. These are optional but recommended. They focus on the harder parts of the course and offer extra questions that help you practice what it will be like when you take the final assessment.
Here's what they look like before you do it and after you do it.
You can do them as many times as you need. Plus, we recommend breezing through all the course questions the night before so that they are in your short term memory; it'll help you get through the assessment much more quickly.