快速答案
cansado 描述感到疲倦的人；cansativo 描述使人疲倦的事物。
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
cansado
tired
Use cansado for the state of a person or animal that lacks energy.
cansativo
tiring
Use cansativo for an activity or situation that causes tiredness.
如何选择
- cansado: Choose cansado if the sentence points to the state of a person or animal that lacks energy.
- cansativo: Choose cansativo if the sentence points to an activity or situation that causes tiredness.
例句
Estou cansado depois da viagem.
I am tired after the trip.
O voo foi longo e cansativo.
The flight was long and tiring.
常见误区
A person can be cansativa when they are wearisome, but to say the person feels tired, use cansada or cansado.
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 cansado，一次用 cansativo。如果两个版本都可以，说明意思怎样变化。