Cycloaddition
n. [化]环加成( 指不饱和分子化合成一环状化合物的反应)
🗣️ 情景例句
Well, I ...
好啦， 我……
How ofter did I tell you to sit straight?
我告诉你多少次要坐正?
A short while ago, my sister helped me to carry one of my old bookcases up the stairs.
几分钟前，我妹妹帮我把一个旧书橱抬上了楼。