由于很多营养素的平均需要量不能很好的确定，所以很难评价rda。

Since the mean requirement for many nutrients is not known with certainty, it is often difficult to establish an RDA.

youdao

由于很多营养素的平均需要量不能很好的确定，所以很难评价rda。

Since the mean requirement for many nutrients is not known with certainty, it is often difficult to establish an RDA.

youdao