Which of the following weather systems is responsible for the "clear autumn air" in the vast areas of northern my country...

Answer D

Answer analysis test question analysis: According to what we have learned about common weather systems and their corresponding weather characteristics, we can know that the weather controlled by warm fronts and cyclonic weather systems is cloudy and rainy. Mainly weather, the weather controlled by the cold front weather system is characterized by cooling and coldness, while "autumn crisp" refers to clear weather, which is formed under the control of anticyclones and mostly occurs in northern areas in autumn every year.

Test point: This question tests the weather system.