A simple blood test can determine whether someone has what most researchers believe is an ideal level of vitamin D of between 30 and 40 nanograms per milliliter of blood.是什么意思_A simple blood test can determine whether someone has what most researchers believe is an ideal level of vitamin D of between 30 and 40 nanograms per milliliter of blood.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句