快速答案
copo 是无柄水杯，xícara 是带柄杯，taça 通常是高脚杯。
可靠的方法是先判断这个词在句子里的功能，再翻译。
每个词的作用
copo
drinking glass or tumbler
Use copo for a handleless everyday vessel for water, juice, and other drinks.
xícara
cup
Use xícara for a small handled cup, especially for coffee or tea.
taça
stemmed glass or goblet
Use taça for a stemmed vessel for wine, sparkling wine, or ceremonial drinks.
如何选择
- copo: Choose copo if the sentence points to a handleless everyday vessel for water, juice, and other drinks.
- xícara: Choose xícara if the sentence points to a small handled cup, especially for coffee or tea.
- taça: Choose taça if the sentence points to a stemmed vessel for wine, sparkling wine, or ceremonial drinks.
例句
Quero um copo de água.
I want a glass of water.
Ela pediu uma xícara de café.
She ordered a cup of coffee.
Serviram o vinho em taças.
They served the wine in stemmed glasses.
常见误区
The container changes the natural measure phrase: um copo de água, uma xícara de café, uma taça de vinho.
放到语境中练习
从你的真实生活中选一个句子，写两遍：一次用 copo，一次用 xícara。如果两个版本都可以，说明意思怎样变化。