A. Micro-lesson is a comprehensive video of sound and text.

B. Micro-courses can't handle animations, but can only record videos.

C. Micro-class is a technology of computer comprehensive processing of sound, text, images and other information.

D. Micro-class takes video as the main carrier, and it takes about ten minutes to record the wonderful teaching and learning activities carried out by teachers around a certain knowledge point or teaching link.

Correct answer: D.