Nitroolefin
硝基烯烃
🗣️ 情景例句
I am sorry. I am not free right now.
对不起，我现在很忙。
How often do you go swimming?
你多久去游一次泳？
We should learn the value of money and learn how many hours' work has to be done before we can buy something.
我们应该认识到钱的价值，知道要干多少小时的活，我们才能买某件物品。