题目

It was a warm April day when a big fat envelope came in the mail from the only college I had ever imagined attending. I tore open the packet. My eyes were   41   on the word “congratulations”. I don’t remember ever smiling so wide.  Then I looked at my     42    package. The cost of my dream school’s tuition, room and board was around $ 40,000- a(n)    43      sum! How could I afford to attend? What good reasons did I have to go there when three other fine colleges were offering me free   44    ? My other choices were good,     45    schools e保护生物多样性最为有效的措施是（　　）A. 建立动植物园 B. 建立濒危物种繁育中心C. 颁布保护生物的多种法律 D. 建立自然保护区