a flock of + plural noun
flock 主要指鸟类或羊群，也可指人群（常带贬义）。
We saw a flock of geese flying south.
我们看到一群大雁向南飞去。
鸟群；一群鸟
flocks — plural of flock
羊群；畜群；人群；一大群人；会众；教友；一绺（毛或发）；毛束；粗绒；填充用粗毛/棉束
A group of birds together, such as during migration.
一群鸟聚在一起,如为了迁徙而聚集的鸟群。
A number of birds together in a group, such as those gathered together for the purpose of migration.
用于床垫的粗羊毛或棉絮
Coarse tufts of wool or cotton used in bedding.
一群动物聚集在一起,尤指羊群,也指山羊、农场动物等
A large number of animals associated together in a group; commonly used of sheep, but (dated) also used for goats, farmed animals, and a wide variety of animals.
一绺羊毛或头发
A lock of wool or hair.
牧师或牧羊人照管的信众
Those served by a particular pastor or shepherd.
细羊毛屑,用于墙纸涂层以产生绒面效果
Very fine sifted woollen refuse, especially that from shearing the nap of cloths, formerly used as a coating for wallpaper to give it a velvety or clothlike appearance; also, the dust of vegetable fibre used for a similar purpose.
一大群人
A large number of people.
宗教会众
A religious congregation.
A flock of geese flew over the lake in a V formation.
一群大雁排成人字形飞过了湖面。
用法提示：此处'flock'指一群鸟（雁），作为名词表示动物群体。
The shepherd led his flock down from the mountain pasture.
牧羊人带领他的羊群从高山牧场下来。
用法提示：此处'flock'指一群羊，是牧羊人管理的动物群体。
The pastor delivered a sermon to his faithful flock on Sunday morning.
牧师在周日早晨向他忠实的会众布道。
用法提示：此处'flock'比喻指教会会众，是牧师的精神羊群。
flock 主要指鸟类或羊群，也可指人群（常带贬义）。
We saw a flock of geese flying south.
我们看到一群大雁向南飞去。
在宗教语境中，flock 指教徒会众。
The pastor preached to his flock every Sunday.
牧师每个周日向他的会众布道。
flocks of 可表示大量、成群的人或物。
Flocks of tourists crowded the square.
一群群游客挤满了广场。
grammar · medium
易错句子There are many flock in the sky.
正确表达There are many flocks of birds in the sky.
flock为可数名词，表示多个群体时需用复数形式flocks，并常用复数结构flocks of.
grammar · medium
易错句子I saw a flock with birds flying over the field.
正确表达I saw a flock of birds flying over the field.
表达‘一群鸟’的正确介词搭配是of，而非with，受中文直译影响容易误用with。
一群鸟
A flock of birds flew over the field.
一群鸟飞过田野。
一群羊
The shepherd led his flock of sheep down the hill.
牧羊人领着他的羊群下山。
牧师的会众
The pastor visited members of his flock who were sick.
牧师探望了他会众中生病的成员。
一群游客
A flock of tourists gathered around the guide.
一群游客聚集在导游周围。
整个羊群（或全体会众）
The farmer sold the whole flock at the market.
农民在市场上卖掉了整个羊群。
与flock（羊群）相伴出现的管理者
类似于flock，但通常指牛、鹿等大型动物群
flock常用于指一群鸟
flock最常修饰的对象，即羊群
羊群（flock）吃草的场所
物以类聚，人以群分
They are all artists, so it's no surprise they hang out together—birds of a feather flock together.
他们都是艺术家，所以经常聚在一起不足为奇——物以类聚，人以群分。
蜂拥而至
Tourists flock to the small town every summer for its famous festival.
每年夏天，游客们蜂拥而至这个小镇，参加其著名的节日。
像一群羊一样（盲从）
The students followed the teacher's instructions like a flock of sheep, without asking any questions.
学生们像一群羊一样听从老师的指令，没有提出任何问题。
物以类聚，人以群分。
Birds of a feather flock together, so it's no surprise they became friends.
物以类聚，人以群分，所以他们成为朋友并不奇怪。
Dictionary facts from ECDICT, WIKTIONARY, WORDNET.