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来源:雅诚德英语网
The problem is that competition ordinarily cannot be observed directly but must be inferred from the spread or increase of one species and the concurrent reduction or disappearance of another species.
问题是,人们通常不能直接观察竞争,而必须从一个物种的扩展或增加和同时另一个物种的减少或消失来推断。