地道 → ☊ di4dao4 
tunnel; causeway ☊ 
Đích thực ☊ 地道 → ☊ di4dao5 authentic; genuine; typical; from a place known for the product; thorough; conscientious ☊ Đích thực ☊ 隧道 ☊ → 坑道 ☊ → 地道 ☊ → 
tunnel