Submicrogram
a. 次(或亞)微克(量)的
??? 情景例句
If you can't get a cab, give me a call. It's not safe to walk home along at night.
如果你叫不到出租車的話，打電話給我，晚上一人走回家不安全。
Four eyes see more than two.
人多識廣。
Look! The bus is coming!
看，車來了！