单选题 The ancient Greeks were much interested in {{U}}speculating{{/U}} on the nature of the world about them.

【正确答案】 D

【答案解析】[分析] 习语辨析 Speculating on表：考虑，推测；而选项A．specializing in擅长于，专攻；B．experimenting on对……进行实验；C．calculating on指望着；D．pondering over沉思，深思；因此D为答案。