cudgel/rack one's brains 煞费苦心

“煞费苦心”，汉语成语，意思是挖空了心思、费尽心机等。可以翻译为“cudgel/rack one's brains，take great pains”等。

例句：

煞费苦心地寻找借口

cudgel one's brains to find an excuse

他们煞费苦心，讨好老板。

They were falling over backwards to please the boss.