单选题 Except for coarse earthen-wares, which can be made from clay as it is found in the earth, pottery is made from special clays plus other materials mixed to achieve the desired results.
【正确答案】 D
【答案解析】coarse粗糙的；crude粗糙的；conventional常规的，符合传统的；unique独一无二的；genuine真正的。