Everyone knows that sun is in the center of the solar system（太阳系）A. aB. anC. theD. /

问题补充：

Everyone knows that sun is in the center of the solar system（太阳系）

A. a

B. an

C. the

D. /

答案：

A. a

B. an

(答案→)C. the

D. /

解析：句意：每个人都知道，太阳石太阳系的中心。sun属于独一无二的物质，故前面加the,故选C.