a hard nut to crack
n.棘手的问题
热门单词
- abdicate from
- ablation moraine
- absorption cost
- Abyssinian
- account to give
- accounting device
- accounting division
- accounting house
- accounting income
- accounting purpose
- accumulated energy
- accumulator tank
- accuracy table
- acellular gland
- acetic thiokinase
- acetochloroanilide
- acetometer
- acetylene urea
- achenocarp
- achromatic doublet
- achromatoplasm
