【正确答案】 C

【答案解析】[听力原文]
   In 1990, over 100 countries signed an international agreement to make it illegal to buy or sell ivory, which is mainly used for jewelry. Most ivory is made from the tusks of African elephants. These tusks are very valuable—one pair is worth more than three times that an African farmer or factory worker earns in a year.
   Hunting elephants was so profitable that from 1979 to 1989 the number of elephants in Africa tell from 1.3 million to 600,000. It was feared that by the year 2000 there would be none left. However, since 1990 there has been much less illegal hunting, thanks to the international agreement.
   But it costs a lot of money to preserve elephants. Game wardens must be hired to protect them, land must be set aside for them, and when they destroy a farmer's crops, the farmer must be paid compensation.
   Zimbabwe and four other African countries say that some of the elephants should be killed legally. This would help keep the population stable, and selling the ivory would help pay for preserving the elephants. But conservationists say that making ivory legal to sell would lead to even more illegal hunting. Others say that it is wrong to kill elephants because they are sensitive animals who feel emotional pain at the death of other elephants.
   Q: What do we learn about the international agreement signed in 1990?
在1990年，100多个国家共同签署了一份国际协议，规定买卖象牙属于违法行为。象牙主要用于制作首饰。大部分象牙是由非洲象的长牙制成。这些长牙极为贵重——一对长牙的价值比一名非洲农民或工厂工人一年收入的三倍还多。
   捕猎大象利润丰厚，以致从1979年到1989年，非洲象的数量从130万头锐减到60万头。人们曾担心到2000年非洲象将会消失。然而，由于这项国际协议的签订，自1990年以来，非法捕猎活动已经减少了很多。
   但保护大象需要花费很多钱。既要雇用狩猎警察来对其进行保护，又要给它们预留出土地，而且，当农民的庄稼遭到大象破坏时，(政府)还要对农民的损失进行赔偿。
   津巴布韦和其他四个非洲国家声称应该合法捕杀一些大象。这样会保持大象数量的稳定，而且卖象牙获取的资金还可以用来保护大象。但自然资源保护主义者称，使贩卖象牙合法化会导致更多的非法捕猎行为。还有人认为捕杀大象是不对的，因为大象是敏感的动物，面对其他同伴的死亡，它们会感到很痛苦。
   快速浏览各题选项，根据其中的关键词ivory、illegal hunting、elephants、tusks、elephant population推测，该短文很可能谈沦的是与捕猎大象、倒卖象牙有关的内容，具体细节需要进一步分析各个选项。
   ①四项均以it为主语，且各自谓语部分为be about, pass a law, announce, be aimed at。
   ②三项都与大象有关(两项提到ivory，一项提到illegal hunting of elephants)。
   结论：本题考查与it有关的内容，且与非法捕猎大象、象牙交易相关，需要注意听it所指代的内容以及与大象及象牙相关的信息。
   本题题干问关于1990签署的那项国际协议，我们能够了解到什么。文章开头就提到，1990年100多个国家共同签署了一份协议，规定买卖象牙为非法行为，C项与此含义一致，故为答案。需注意C项是对原文的同义转述，原文中buy or sell ivory在正确选项中被转述为make any transactions of ivory。