a hard nut to crack
n.棘手的问题
热门单词
- abnormal growth
- abraxas
- abscission joint
- absolute pressure indicator
- absorption coefficient
- absorptionpyrometer
- abstract sound
- abut
- acanthopterygian
- accessory risks
- accessory substances
- accidentalism
- accommodating transaction
- acetoxime
- acetylamidoazotoluene
- acid oxalate
- acidified milk
- acidophilic erythroblast
- acorn sugar
- acoustic coupler
- acoustic dazzle