---The vase cost me almost 100 yuan.-Well it was crazy of you to spend so much money y

问题补充：

---The vase cost me almost 100 yuan.

---Well, it was crazy of you to spend so much money you could buy a much cheaper one.

A. while

B. if

C. because

D. when

答案：

A. while

B. if

C. because

(答案→)D. when

解析：when 作“既然”讲，语气较强烈。