Teachers can control the units, weeks, and articles that students have access to in the Table of Contents. From the Table of Contents in the teacher account, simply toggle the button to the right of each unit, week, or article.
Teachers can also use the toggle to hide or unhide weekly assessments, Crossword, and Misspilled games.
Recommendation
If you don't want students to look back at articles while they take an assessment, you can use the toggles to hide articles for that week in the Table of Contents.
The three dots 
at the top of the Table of Contents allows you to hide or unhide all weeks, weekly assessments, Crossword, or Misspilled games.
To learn more, see the How to Navigate the Table of Contents article.