Tony glanced at her, then did a double take .

托尼瞥了她一眼，过后才恍然大。

The speaker gave us a humorous joke which suddenly clicked with us and we all laughed.

"演说的人给大家讲了个话,使我们一下子恍然大,我们都哈哈大起来。"

I wasn't used to such good treatment, then it clicked : we were wearing suits.

我不习惯有礼的招待，随后我恍然大：因为我们穿着西装。