Letters and solar terms

(1) As can be seen from the earth revolution diagram, when the earth revolves to place A, the sun shines directly at the equator, which is the vernal equinox in the northern hemisphere; When the earth revolves to B, the sun shines directly on the Tropic of Cancer, which is the summer solstice in the northern hemisphere. The earth revolves to C, and the sun shines directly on the equator. At this time, it is the autumn equinox in the northern hemisphere; When the earth revolves to D, the sun shines directly on the Tropic of Cancer, which is the Tropic of Cancer.

(2) As can be seen from the picture, when the earth revolves to position A, the sun shines directly at the equator, which is the vernal equinox in the northern hemisphere, and the length of day and night in China is equal; When the earth revolves to position B, the sun shines directly on the tropic of cancer, which is the summer solstice in the northern hemisphere, that is, around June 22. When the earth rotates to the D position, the sun shines directly on the tropic of Capricorn, which is called the winter solstice.

So, the answer is: (1) vernal equinox; Summer solstice; Vernal equinox; Solstice of winter; (2) the equator; Equality; Tropic of Cancer; Around June 22; Tropic of Capricorn; Solstice of winter.