补全短文
Rough estimates in the past have predicted similarly disappointing results. ________ Says Sallie Chisholm， an environmental engineer from the Massachusetts Institute of Technology. "But the take-home message is the same. Ocean fertilization is not the answer to global warming."
A、"These are newer and better models，"
B、Its opponents argue, however, that it will stop global warming.
C、Adding iron to patches of ocean can make plankton bloom temporarily.
D、As plankton die and settle on the ocean floor, their carbon is supposedly locked up in the seabed.
【正确答案】 A
【答案解析】 这个问题可以根据引号来作答，因为空格后面有“says”这个词，它预示着所填入的句子应该是带引号的。A的意思是：这些是比较新的也是比较好的模型。
