意思是：那都是空谈 / 光说不做 / 说得好听而已。

词语解析

• That's = That is，那是
• all = 全部、完全
• talk = 谈话、空谈

这里的 talk 不是普通的“谈话”，而是指没有实际行动或事实支撑的言论。

例句

1. He promises a lot, but that's all talk.
他承诺了很多，但都是光说不做。

2. I don't believe him. That's all talk.
我不相信他，那都是空谈。

3. Actions speak louder than words.
行动胜于言语。

注意：That's all talk 带有明显的怀疑、不相信或批评的语气。