casually

• 随口回答

  casually reply

• 随口乱讲

  ramble on thoughtlessly

• 随口附和

  casually echo

• 既然不知道，你就别随口乱说。

  If you don't know then don't talk rubbish.

• 他随口答应了，而后来又不办。

  He casually agreed but then he did not do it.

• 这是他随口说的，而事情并不这样。

  He just said that casually. It is not really like that.