weather

Test analysis: As can be seen from the figure, both places are low-pressure centers. A is the frontal cyclone in the northern hemisphere, indicating that ① is the side of the cold air mass, pushing the cold air mass to move south, ② is the side of the warm air mass, ② is pushing the warm air mass to move north, and M is the warm front. The precipitation before the warm front is on the m side, and the southerly wind blows on the east side of A, and A is wrong and D is wrong. B is a frontal cyclone in the southern hemisphere, and updraft prevails in the center. B is wrong. As can be seen from the figure: ④ It is the side of the cold air mass, ④ pushing the cold air to move northward, ③ it is the side of the warm air mass, pushing the warm air to move southward; N is behind the warm front, it should be after the rain. C is correct.