学习班的英文：
courses

Some of the students went to summer sessions to accelerate.
有几个学生参加了暑期速成学习班。

Since I also have trouble in English grammar, I attend an English class to study grammar.
由于我在英语语法上也存在困难， 我参加了一个英语学习班学习语法。

Within weeks Mr. Aylott was running workshops and staging performances inside.
几周之内，艾洛特在监狱里举办了学习班并进行表演。

a bobsleigh course
大雪橇滑道

It is not, of course, exhaustive
当然这是不够详尽的。

In college, English is a required course and psychology is an elective course.
在大学里，英语是必修课而心理学是选修课。

The checks are all good, of course.
当然，这些支票是完全有效的。

Of course, this can be abused.
当然了，这样还是可能会被滥用。