How do you know when 会 means will and when it means can?
The sentence was 你会唱英语歌吗 and I put "Will you sing English songs" And it was wrong and the correct answer is "Can you sing English songs?"
Depending on the situation, it could be translated either way. I would report it as correct and see if they add it to the possible solutions.
In real life conversations, you would infer the meaning based on the context.
It's hard to tell, I know. Usually, it depends on the situation. However, the usual definition is "can" because it sounds chunky in Chinese if you were for it to mean Will you sing English Songs. As a native speaker, I would say "唱个英文歌吧". I don't know, it depends how much practice you've had with Chinese speaking people. When I saw the sentence, I immediately knew it meant "Can you sing English songs?"
I hope this helped you, good luck!