(2) Among A and B, the seasonal precipitation of A is larger, and the annual precipitation of B is larger;
(3) According to the characteristics of temperature and precipitation in A and B, A belongs to temperate monsoon climate, with warm and rainy summer and cold and dry winter, while B belongs to subtropical monsoon climate, with high temperature and rainy summer and mild and little rain in winter.
(4) Affected by the alternation of winter and summer monsoon, most parts of China are cold and dry in winter and hot and rainy in summer.
So, the answer is: (1) a; b; (2)b; a; (3) temperate zone; Subtropical; (4) cold and dry; It is hot and rainy.