What conditions do I have to meet to continue to the next semester?

You must gain at least 20 credits in the last semester or 45 credits in the last two semesters and successfully complete all the courses you have repeated in the semester immediately preceding.
You must also apply in the appropriate period (see the Schedule) via the IS for enrolment in the next semester. The instructions for this procedure are available in Help with IS.

For more information see (czech only) Study and Examination Rules, art. 12.

How many credits are required to continue to the next semester: 20 or 45?

OR means either one or the other option. In order to continue to the next semester you will need to gain either 20 credits for the last semester or 45 credits for the last two semesters. 

E.g.: You will meet the requirements for continuing to the Spring 2010 semester if you gain 43 credits in the period Spring 2009 and only 2 credits in the period Autumn 2009.

Tip: This option is often used by students when they go on a planned stay abroad.

What will happen if I do not gain 20 credits per semester (or 45 credits over the last two semesters)?

You will fail to meet the conditions  for continuing in the next semester and your study will be terminated.

For more information see the (czech only) Study and Examination Rules, art. 12.