Subject + 是不是 + Predicate / 是不是 + Clause
是不是 (shì bu shì) is used to form yes-or-no questions by seeking confirmation from the listener. It can be placed at the beginning, middle, or end of a sentence to turn a statement into a question expecting agreement or denial.
你是不是已经吃过饭了?
Nǐ shì bú shì yǐjīng chī guò fàn le?
Have you already eaten?
这件事是不是他告诉你的?
Zhè jiàn shì shì bú shì tā gàosu nǐ de?
Was it him who told you about this?
明天的会议是不是取消了?
Míngtiān de huìyì shì bú shì qǔxiāo le?
Has tomorrow's meeting been canceled?