a/an + swan
swan为可数名词，单数前需用冠词。
A swan flew over the trees.
一只天鹅飞过了树林。
天鹅
swans — plural of swan
姿态优雅的人；像天鹅般优美的人；悉尼天鹅队相关人员（球迷、球员、教练等）；斯旺西城足球俱乐部相关人员（球迷、球员、教练等）；天鹅纹章（有时颈戴王冠）；天鹅属(Cygnus)多种大型长颈水禽的通称,大部分羽毛白色。
a large water bird with a long neck, usually white-feathered as an adult
天鹅属(Cygnus)多种大型长颈水禽的通称,大部分羽毛白色。
Any of various species of large, long-necked waterfowl, of genus Cygnus (bird family: Anatidae), most of which have white plumage.
与悉尼天鹅队有关的人,如球迷、球员、教练等。
someone connected with the Sydney Swans, as a fan, player, coach, etc.
与斯旺西城足球俱乐部有关的人,如球迷、球员、教练等。
someone connected with Swansea City Football Club, as a fan, player, coach, etc.
一种姿态高贵、体型粗壮、颈极长的水鸟,成鸟通常有白色羽毛。
stately heavy-bodied aquatic bird with very long neck and usually white plumage as adult
姿态优美如天鹅的人。
One whose grace etc. suggests a swan.
用作纹章图案的天鹅,有时颈上有王冠(如白金汉郡徽章)。
This bird used as a heraldic charge, sometimes with a crown around its neck (e. g. the arms of Buckinghamshire).
We saw a white swan swimming across the lake this morning.
今天早上我们看到一只白天鹅游过湖面。
用法提示：swan 在此作可数名词，指‘天鹅’。
The swan stretched its long neck and spread its wings.
那只天鹅伸长脖子，展开双翅。
用法提示：swan 为名词，指‘天鹅’，用单数形式。
Many swans gather here every winter before flying south.
每年冬天，许多天鹅在飞往南方前聚集在这里。
用法提示：swans 是 swan 的复数形式，表示多只天鹅。
swan为可数名词，单数前需用冠词。
A swan flew over the trees.
一只天鹅飞过了树林。
The swan was swimming gracefully.
那只天鹅优雅地游着。
所有格形式表示天鹅的某部分或所属。
The swan's neck is long and curved.
天鹅的脖子又长又弯。
常用复数形式swans表示群体。
A flock of swans migrated south for the winter.
一群天鹅向南迁徙过冬。
grammar · medium
易错句子I saw two swan in the park.
正确表达I saw two swans in the park.
中文缺少复数变化，学习者常遗漏复数词尾 -s；英语中可数名词复数需加 -s。
grammar · medium
易错句子Look at swan! It is beautiful.
正确表达Look at the swan! It is beautiful.
汉语没有冠词，学习者易遗漏；英语中单数可数名词前需加冠词。
白天鹅
A white swan glided across the lake.
一只白天鹅滑过湖面。
黑天鹅
The discovery of a black swan surprised the ornithologists.
发现黑天鹅让鸟类学家们惊讶。
疣鼻天鹅
Mute swans are common in parks and lakes.
疣鼻天鹅在公园和湖泊中很常见。
绝唱；最后的作品
This performance was her swan song before retirement.
这场演出是她退休前的绝唱。
燕式跳水
He executed a perfect swan dive off the high board.
他从高台跳板上完成了一个完美的燕式跳水。
绝唱；最后作品
The concert was her swan song before retiring.
这场音乐会是她在退休前的绝唱。
黑天鹅事件（指罕见且影响重大的事件）
The financial crisis was a black swan event that caught everyone off guard.
金融危机是一个让所有人措手不及的黑天鹅事件。
我是天鹅女王。
Line from the film 'Black Swan' (2010), spoken by the protagonist Nina.
电影《黑天鹅》（2010）中主角妮娜的台词。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.