"Two buttons" is the most common way to say "两粒纽扣" in Engpsh. The word "button" comes from the Old French word "bouton," which means "knob" or "button." In Engpsh, a button is a small, round object that is sewn onto clothing and used to fasten or secure the garment.
Here are some examples of "button" being used in sentences:
"I need to sew a button back onto my shirt." (我需要把一个纽扣缝回我的衬衫上。)
"Please button up your coat before we go outside." (请在我们出门前扣上你的外套。)
"I accidentally popped off one of the buttons on my jacket." (我不小心把我夹克上的一个纽扣弹掉了。)