50. What does the author imply by saying aquaculture is no silver bullet?
A) Shrimp-farming is a risky business.
B) Fish-farming will not be sustainable.
C) Fish-farming may cause serious problems too.
D) Shrimp-farming can become quite expensive.
（本题出自2022年12月四级真题卷二）
答案&解析：
50.C)
【精析】细节辨认题。最后一段第二句指出，在一些东南亚国家，虾类养殖对海洋生态造成了灾难性的破坏。由此可知，水产养殖也有负面影响，故答案为C。
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