crystal clear

1 (of glass, water, etc) entirely clear （指玻璃、 水等）完全透明的. 2 (fig 比喻) very easy to understand; completely understood 浅近易懂的; 明明白白的: She made her meaning crystal clear. 她把她的意思解释得清清楚楚.

crutch, crux, cry, cry down, cry for, cry off, cry out, cry-baby, crybaby, crying, cryogenic, cryogenics, crypt, crypt(o)-, cryptic, cryptically, cryptogam, cryptogram, crystal, crystal ball, crystal set, crystal-gazing, crystalline, crystallization, -isation, crystallize, crystallize, crystallise, crystallized, -ised, CSE, CSM, CST, ct, cu, cub, cub reporter, cubby-hole, cube, cube root, cubic, cubical, cubicle,