学时的英文：
class hour
period

参考例句：

Shirley was consumed with love for John during their days at university
在大学时，雪莉倾心爱着约翰。

Their friendship flowered while they were at college.
他们的友谊在求学时已根深蒂固。

I preferred soccer to other sports when I was in middle school.
较之其他体育项目，我在中学时更喜欢踢足球。

He was indefatigable in his lectures on the aesthetics of love
在讲授关于爱情的美学时，他是不知疲倦的。

Did you major in jonrnalism in college?
你大学时主修新闻学吗？

He was not good at algebra in middle school.
他中学时不擅长代数。

I recognise my primiary schoolmate Mary in the photo.
我从照片上认出了我小学时的同学玛丽。

Let me cite an incident that happened last semester as an example.
就举我上个学期在美国求学时的例子吧。

I lost her when she started speaking aBout thermodynamics.
当她开始讲热力学时，我理解不了。

Children learn to print when they first go to school.
儿童刚入学时学习用印刷体写字。

class是什么意思：
n. 班级；阶级；种类
v. 分类；把…分等级
adj. 很好的

It is a step class.
这是踏板操训练班。

The class dismissed.
下课了。

The class teacher sectioned the class for dialogues.
老师把班级分组进行对话练习。

hour是什么意思：
n. 小时；长时间；时刻；重要时刻；某个时间；整点；（工作办公的）固定时间

by the hour together
连续几小时|不断地

They enjoyed marching around the room hour after hour.
他们喜欢绕着房间一小时又一小时地行进。

We did an hour of gym.
我们做了一小时的体操。

period是什么意思：
n. 时间；时期；周期；经期；课时；局；句号
adj. 某一时期的；当时特有的

juvenile period
幼年期(构成中心木质部的一段时期)

But this is a transitional period.
但这是个转变过程。

The period includes the legal period and the period designated by the people's court.
期间包括法定期间和人民法院指定的期间。