the wall have ears 不是“墙上长了耳朵”，而是应该聪明地意译为“隔墙有耳”。

【例句】
Let's talk in my office - out here, the walls have ears.
到我办公室里谈吧，这里当心隔墙有耳！

Watch your mouth! The walls have ears.
说话当心点儿，隔墙有耳。