What is the weather system that causes "rainy and sunny, cold north wind"?

Influenced by cold air mass and clear weather at night, the atmospheric inverse radiation is weak. 8. "Chu Qingyu, the north wind is cold" is caused by which of the following weather systems (b)

A. Cold front crossing

C. effects of tropical marine air masses

9. "Chu Qingyu, the north wind is cold" causes "night frost". The reasons are (1)

A. Due to the influence of cold air mass and clear night, the atmospheric inverse radiation is weak. B.the temperature must be very low at night after the rain.

C. on a clear night, the ground radiation is very weak. D. On a clear night, the ground radiation increases.

10. The principle of "setting fire to the body, smoking less, frost-free" is (a)

(1) "Smoke enhances the inverse radiation of the atmosphere, so that the ground temperature will not drop too fast; ② "Smoke" is mainly composed of carbon dioxide, which has obvious thermal insulation effect on the ground; ③ "Make a fire to cook" and directly heat the ground; (4) "making a fire to cook" will directly smoke and warm the atmosphere.

A.①② B.③④ C.①③ D.②④