When the earth revolves to D, the solar terms in the northern hemisphere are () A, vernal equinox B, summer solstice C, autumn equinox D and winter solstice.

Analysis: Look at the map, A is the autumnal equinox, B is the winter solstice, C is the vernal equinox, and D is the summer solstice. When the earth revolves to D, the solar term in the northern hemisphere is the summer solstice. When the sun shines directly on the Tropic of Cancer, the days in the northern hemisphere are long and the nights are short. So choose B. Comments: This question examines the schematic diagram of the earth's revolution and can be solved by reading the picture.