A. High brightness, B. Long life, C. Large viewing angle.
Analysis:
The main features of LED display screens include many aspects. According to the options given in the question, we can analyze them one by one:
A. High brightness: LED display screens do have the characteristics of high brightness, which enables them to maintain good visibility under various lighting conditions, especially in outdoor environments, and can still clearly display the content of the picture. Therefore, option A is a main feature of LED display screens.
B. Long life: The life of LED display screens is relatively long, generally up to tens of thousands of hours. This is due to the high reliability and long life characteristics of LED lamp beads. Therefore, option B is also a main feature of LED display screens.
C. Large viewing angle: LED display screens have a wide viewing angle range, which can provide a large viewing angle in both horizontal and vertical directions. This means that viewers can get good visual effects when watching from different positions. Therefore, option C is also a main feature of LED display screens.
In summary, options A, B, and C are all main features of LED display screens. Therefore, the correct answer is A, B, and C.