Dr.Huerta says many Latin and South American communities do not have mammography machines, and there is a general lack of knowledge about the disease.
VOA: standard.2010.02.02
to express a lack of complete knowledge about the multitude of subjects.
它可以用来表达你对一些话题并不完全了解。
but also very non-affrontively, express a lack of complete knowledge
又不冒犯地表达对某事不完全清楚,
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