刻苦钻研

• 亥(twelfth earthly branch (pig))PHONETIC
• 刂(blade; knife edge)RADICAL

Using a knife to carve into a surface creates a deep mark.

• 艹(grass; plant)RADICAL
• 古(ancient; old)PHONO-SEMANTIC

An ancient grass variety carries a bitter, acrid, and harsh taste.

• 釒(metal)RADICAL
• 贊(praise; support)PHONETIC

A metal drill bit spirals forcefully into material like heartfelt praise piercing deep into someone's heart.