题目：
The ancient Greeks were much interested in speculating on the nature of the world about them.
A．specializing in
B．experimenting on
C．calculating on
D．pondering over
答案：
参考答案：D
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。
