C.a series of 一连串,一系列
"一系列的丰收使得农民们生活富足"
a set of 一套;一副（家具）
a pair of 一双；一对；一副（裤子/鞋子/袜子/眼镜等由两个组成的一对）
a piece of＋不可数名词 一个/块/条...
a piece of news/paper/cake/chalk
We have a set of table glass.
我们有一套玻璃餐具.
He has a set of ugly furniture.
他有一套难看的家具.
The theory is based on a series of wrong assumptions.
这一理论是以一系列错误的设想为依据的.
A series of mischance happened.
一连串不幸的事发生了.
A series of propaganda activity.
一系列的宣传活动.
I want to buy a pair of pants.
我想买一条长裤.
I want a pair of sports shoes.
我想要一双运动鞋.
The baby was given a piece of candy.
这孩子拿到了一块糖.
I'd like a piece of chocolate.
我想要吃块巧克力.
Please give me a piece of pie.
请给我一张馅饼.