Great changes in our city. It is no longer it used to be ten years ago.A. took place how

问题补充：

Great changes in our city. It is no longer it used to be ten years ago.

A. took place, how

B. have taken place ,what

C. are taken place, which

D. take place ,when

答案：

A. took place, how

(答案→)B. have taken place ,what

C. are taken place, which

D. take place ,when

解析：考查时态及名词性从句。根据句意：我们的城市发生了巨大的变化，用现在完成时态。What引导表语从句，在从句中作表语，故选B。