concave surface是什么意思？

• repeat
• vehicle
• droplets
• cloud
• 方案英语
• brat
• supper
• PEGGING
• searches
• conflict
• tourist
• 领域英语
• giraffe
• scared
• monitor
• rice
• toxicity
• searches
• algiers
• fiercely
• 纪念品英语
• silver
• begins
• firmness
• autumn
• lesson
• default
• prompt
• amazing
• 解决方案英文

• bothering
• theatre
• modernize
• pear
• juice
• panicked
• mind
• polite
• 抛弃英文
• approaches
• profile
• peeping
• client
• reveal
• lake
• satisfaction
• candy
• aspect
• cheese
• disappointed
• 参与者英文
• tomato
• permitted
• 呼吁英语
• organizations
• passage
• 队长的英文
• neck
• 确认英文
• intermission

• at a time
• at all
• at any rate
• at bay
• at hand
• at large
• at last
• at least
• at length
• at long last
• at once
• at one time
• at present
• at the same time
• at times
• attach to
• attend to
• back and forth
• back down
• back out
• back up
• bay window
• be born
• be bound to
• be made of
• bear away
• bear down
• bear in mind
• bear off
• bear on