The traditional houses in the three northeastern provinces have thick walls and steep roofs, so it can be judged that the climatic characteristics of the three northeastern provinces are mainly () A.

The traditional houses in the three northeastern provinces have thick walls and steep roofs, so it can be judged that the climatic characteristics of the three northeastern provinces are mainly () A. Cold and dry B. The building structures in various parts of China are closely related to the local climate. Due to less precipitation and low temperature in winter in most parts of northern China, flat-topped houses with small slopes have been built without considering drainage problems on the roofs. In order to resist the cold in winter, the walls are thicker and the windows are smaller. There is more precipitation in the south, with hot summer and mild winter. In order to facilitate drainage, the roof slope is large, the wall is high and the windows are large, which is convenient for ventilation and heat dissipation in summer. In Northeast China, due to the cold and humid climate in winter, there is more snowfall, the roof slope is larger, the wall is thicker and the windows are smaller.

So choose: C.