Mnng
N-甲基-N'-硝基-N'-亞硝基胍
??? 情景例句
she would call us.
她會(huì)打電話過(guò)來(lái)的。
In college I majored in science.What was your major?
在學(xué)院我主修了自然科學(xué)，你主修了什么？
Was there a message?
留話了嗎？