It set the daily amount at 200 international units from birth through age 50.It set the level at 400 I.U.s through age 70, and 600 for age 71 and older.是什么意思_It set the daily amount at 200 international units from birth through age 50.It set the level at 400 I.U.s through age 70, and 600 for age 71 and older.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句