a piece of 修饰不可数名词，比如：a piece of paper 一张纸，如果想说两张纸的话要说two pieces of paper, 在piece后面加s。
一张纸：a piece of paper一块玻璃：a piece of glass
一片面包：a piece of bread
一片奶酪：a piece of cheese
一块树皮：a piece of bark
一片肉：a piece of meat
一块木头：a piece of wood
一块布：a piece of cloth
more than two but fewer than many (可以理解为several), 前面一般用形容词修饰，比如a large number of 许多 或者是 a small number of 一小部分。用来修饰可数名词复数。
一些选择：a number of options
一些人：a number of people
- plenty of 大量 ; 充裕的
an abundant amount of; more than is needed. 强调很多，比需要的多。用来修饰可数复数和不可数名词。
许多鱼：plenty of fish
许多时间：plenty of time
许多麻烦：plenty of trouble
许多人：plenty of people
充足的空间：plenty of room
an amount of 数量；数额
an amount of sth. 修饰不可数名词。与 a number of 相对，a number of sth. 修饰可数名词复数。
一段时间：an amount of time
一笔钱：an amount of money
一些信息：an amount of information
大量研究：an amount of research
a quantity of / quantities of 一些
quantity is more formal than amount or number. quantity比amount还有number更正式。a quantity of 和quantities of 可以修饰可数名词复数和不可数名词。可以用large, big, small,huge修饰。
一些武器：a quantity of weapons/ quantities of weapons
一些食物：a quantity of food/ quantities of food
a deluge of 纷至沓来的；蜂拥而至的
a very large volume of sth. more than can be managed. 常见修饰可数名词复数，下面这几种搭配最常用。
蜂拥而至的参观者：a deluge of visitors
蜂拥而至的抱怨/信件/电话/要求：a deluge of complaints/letters/calls/requests
a mound of/ mounds of 一堆
(informal)，常见修饰土，不正式，比如：a mound of paperwork. 一堆文件。
一堆土：a mound of dirt
一堆堆土：huge mounds of dirt
一大堆衣服：a large mound of laundry
a myriad of/myriads of 大量；各种各样
a myriad of or myriads of people or things is a very large number or great variety of them. 强调各种各样的大量的。
各种问题：a myriad of problems/myriads of problems
各种颜色：a myriad of / myriads of colours
各种活动：a myriad of / myriads of activities
各种原因：a myriad of / myriads of reasons
各种挑战：a myriad of / myriads of challenges
a flock of 一群（鸟或羊）
a flock of 修饰 birds, sheep, goats. a flock of / flocks of 还可以修饰人，表示强调这里有一大群人（可能发生了什么使得人群聚集）
一群鸟：a flock of birds
一群绵羊： a flock of sheep
一群山羊：a flock of goats
一群人：a flock of people/ flocks of people
一群记者：a flock of reporters/flocks of reporters
