to (cause something or someone to) have difficulty imagining or understanding something

My mind boggles at the amount of money they spend on food. 我不明白他们为什么在食物上花那么多钱。

It boggles the imagination, doesn't it? 难以想象，对吧？

See also: mind-boggling

to be very surprised and uncertain about how to deal with something

He boggled at the suggestion. 他对这个建议犹豫不决。