Stephen Hawking believes that the earth is unlikely to be the only planet _life has develo

问题补充：

Stephen Hawking believes that the earth is unlikely to be the only planet _life has developed gradually.

A. that

B. where

C. which

D. whose

答案：

A. that

(答案→)B. where

C. which

D. whose

解析：考查定语从句。Where在从句中做状语。“霍金认为地球不可能唯一有生命进化的星球。”