同学你好，该知识点来自沪江网校《新概念英语1、2、3、4册连读【限时特惠班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
drill 是反复练习，比如我们上课老师反复让同学练习从句等
The teacher runs them through a drill — the days of the week, the weather and some counting. 老师带他们做了反复练习：一周中每一天的叫法、天气和数数。

practice一般指实践训练
She was taking all three of her daughters to basketball practice every day.
她每天都带3个女儿进行篮球训练。

exercise 可以指一些习题等或者身体上的锻炼
Try working through the opening exercises in this chapter.做一做本章节的开篇习题。
She exercises two or three times a week. 她每周锻炼两三次。

train 表示“培训”
The US was ready to train its troops to participate.
美国准备训练军队参加。

祝同学学习进步~