1.period的基本意思是“一段时间”,是可数名词,复数形式为periods。
2.period可作“时期,时代”解,指某个历史阶段或时期; 也可作“课时,学时”解; 还可作“月经(期)”解。
3.在美式英语中period的意思是“句号,句点”,相当于英式英语的a full stop。
4.period与定冠词the连用,意思是“现代,当代”。

The students' lunch period is from 11：30 to 12：30.学生们的午餐时间是从11点半到12点半。
Mary was restored to health after a period of medical treatment.经过一段时间治疗,玛丽康复了。
We lived in Beijing for a period.我们在北京住过一段时间。
She was taken on for a three-month trial period before being accepted as a permanent member of staff.在她被接受为固定雇员之前经过了三个月的试用期。
The work must be completed within a two-month period.工作须于两个月内完成。
There were long periods when we had no news of him.我们曾有好长时期没有得到他的消息。
He excels all other composers of his period.他胜过同时代的所有其他作曲家。
We have entered upon a new period of history.我们进入了一个新的历史阶段。
It was the most glorious period of the Roman Empire.这段时期是罗马帝国最辉煌的时期。
They were young at the period of their entrance upon the stage of history.在他们登上历史舞台的时代,他们还很年轻。
The cavemen lived in a period of history antecedent to written records.山顶洞人生活在有文字记载之前的一个历史时期。
During the Warring States period, more walls were put up to defend the borders of the different kingdoms.战国时期,修建了更多的城墙来保卫不同王国的边境。
The Ming period declined.明朝衰落了。
The school day is divided into seven periods.学校一天有七节课。
We have four periods before noon.上午我们有四节课。
Each school day has six periods with a ten minute recess between.每一个上课日分为六节,中间各休息十分钟。
Use a period at the end of the sentence.在一个句子的末尾用句号。
The period marks the end of a sentence.句号标明一句话的结束。
There should be a period at the end of a declarative sentence.陈述句的末尾应该有一句号。
Ross is a girl of the period.罗斯是个现代姑娘。
He is the youth of the period.他是一个现代青年。
My period is only for half a day and I get terrible headaches.我月经来时通常只有半天,而且头痛得厉害。
She had never had her period before.她以前从没来过月经。

period, age, generation
这三个词的共同意思是“时期”。其区别是：period是这组词中最一般的常用术语,用于任何时限,时间可长可短; age意为“时代,寿命”,常用来表示以一个中心人物或显著特征而闻名的时期; generation意为“代、世代”,用于上辈出世与下辈出世之间的时段,对人类来说这段时间有时可算作20年或25年,也可用于下辈本身。例如:
The period in which people learnt to make tools of iron is called the Iron Age.人类学会用铁制造工具的时代,我们称为“铁器时代”。
My generation behaves differently from my father's and grandfather's.我这一代人和我父辈及祖辈表现不同。

1.正常上课的日子有六节课。
［误］  There are six lesson period in a normal school day.
［正］  There are six lesson periods in a normal school day.
［析］  period作“学时、课时”解时有复数形式。
2.在那些动乱年代里,我们在农场呆了很久。
［误］  During those years of turmoil, we stayed on a farm for a long period of time.
［正］  During those years of turmoil, we stayed on a farm for a long time.
［析］  误句中的period of是多余的,应删去。

period还可用作感叹词,位于句末或句中。常常是说话人在讲过某句话之后又作的补充,强调说话人对事件的态度明确,用不着再解释了。例如:
I could have prevented them,and I didn't.Period.我本来能够阻止他们,但是我并没阻拦,就这样。
I love her, period!我爱她,就是爱她!

［同义词］   age, epoch, era, interval, term, time
［词源］  ＜拉丁语periodus＜希腊语periodos(循环,走一圈)