each refers to an individual object or person.
Each指的是一个单独的物体或人。
If you refer to each thing or each person in a group, you are referring to every member of the group and considering them as individuals.
如果你指的是一个群体中的每一件事或每一个人，你指的是这个群体中的每一个成员，并把他们视为个体。
every refers to a group of objects or people.
Every指的是一组物体或人。
You use every to indicate that you are referring to all the members of a group or all the parts of something and not only some of them.
你可以用every来表示你指的是一个团体的所有成员或某物的所有部分，而不仅仅是其中的一部分。
例:
each:
Each one of those new cells has a new copy of your DNA.
每一个新细胞都有一个你DNA的新副本。
Each book is beautifully illustrated.
每本书都配有精美的插图。
Each year, hundreds of animals are killed in this way.
每年，数百只动物就是这样被杀死的。
every:
Every single one of you will receive a treat.
你们每个人都会得到一份奖励。
Every room has a window facing the ocean.
每个房间都有一扇面对大海的窗。
