a hard nut to crack是什么意思？

• maths
• vehicle
• autumn
• 确认英文
• 导师英文
• neck
• 呼吁英语
• theatre
• 旋律的英文
• erased
• searches
• profile
• 实施英文
• satisfaction
• permitted
• intermission
• giraffe
• panicked
• cheese
• prompt
• 长颈鹿英语怎么说
• 局外人英文
• passage
• text
• amazing
• committing
• failure
• 纪念品英语
• monitor
• juice

• brat
• candy
• banger
• lesson
• sweater
• ultra
• 缺陷英文
• modernize
• emergency
• conflict
• chess翻译
• organizations
• repeat
• supper
• giraffe
• 抛弃英文
• toxicity
• PEGGING
• pear
• passage
• default
• 造型的英文
• general
• reveal
• various
• front
• saturday
• rice
• general
• 流浪者英文

• build up
• building block
• building complex
• bump into
• burial site
• buy off
• by all means
• by all odds
• by and large
• by means of
• by no means
• by the way
• call back
• call for
• call in
• call off
• call on
• call up
• calm down
• carbon dioxide
• care for
• carry away
• carry off
• carry on
• carry out
• catch on
• catch up with
• center on
• change over