题目解析：
【题目翻译】作者在第3段中对bt植物对非目标生物体的影响作了什么结论？
A：Bt毒素不会影响非目标生物，因为这些毒素只会伤害吃植物叶、茎或果实的害虫。
B：Bt植物已在野外研究中被证明对非目标生物有很大的危害。
C：BT植物对非目标物种的危害没有传统杀虫剂那么大。
D：即使bt毒素不会影响以植物为食的昆虫，它们也会对吃这些昆虫的鸟类产生有害影响。
【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。
【关键词定位】本题的出题点在第五段最后两句：However, field tests indicate that Bt corn is not likely to harm monarchs. Furthermore, the application of pesticides (the alternative to growing Bt plants) has been demonstrated to cause widespread harm to nontarget insects. 意思是“然而，田间试验表明，Bt玉米不太可能危害帝王。此外，杀虫剂（替代种植Bt植物）的应用已被证明对非目标昆虫造成了广泛的危害”。
【逻辑分析】这两句对比说明Bt作物不会伤害毛毛虫，但是杀虫剂的使用是会伤害它们这种非靶向物种的。
【选项分析】
A.选项A说Bt物质不会伤害非靶向物种，错误，只是伤害比杀虫剂小而已；
B.选项B说Bt物质杀伤力非常大，错误，其实并不大；
C.选项C说Bt植物对非靶向物种的伤害比杀虫剂小，正确。
D.选项D说即使Bt物质不伤害以这种作物为食的昆虫，但是会伤害鸟类，错误。
On the negative side, opponents of transgenic crops suggest that there are many questions that need to be answered before transgenic crops are grown on a large scale. One question deals with the effects that Bt plants have on nontarget organisms such as beneficial insects, worms, and birds that consume the genetically engineered crop. For example, monarch caterpillars feeding on milkweed plants near Bt cornfields will eat some corn pollen that has fallen on the milkweed leaves. Laboratory studies indicate that caterpillars can die from eating Bt pollen. However, field tests indicate that Bt corn is not likely to harm monarchs. Furthermore, the application of pesticides (the alternative to growing Bt plants) has been demonstrated to cause widespread harm to nontarget insects.
