(b) Although relevant data were collected in some regions, such measurements were not done systematically and, often, the lack of adequate control measures meant that the quality of the data could not be guaranteed;
（b） 虽然有些区域收集了相关数据，但测量工作做得不系统，往往缺少适当的控制措施，这就意味着数据质量无法保证；