救命紧急提问英语解释并举出例子

解释下列词组、举例子
1、elected course\optional course
It's a college class which you may take or which you may not take. It all depends whether you like it or not.
2、required course
It's a college class which you are mandated to take, whether you like it or not.
3、graduation practise
A certain period of time that you work as an intern or trainer.You apply what you have learned at school to the real world
4、professional skills
knowledge, strategies that you have learned or you have mastered in your field.

第一个好像错了 elective course为选修课
2.必修课
3.毕业实习
3.专业的技能
例子:
1.German德语 Japanese日语 Russian俄语 art美术 music音乐
2.Chinese语文 math数学 physics物理 chemistry化学 geography地理
3.cadet teacher实习教师 medic实习医生
4.manicure修指甲术 brede刺绣术

1.选修课
2.必修课
3.毕业实习
4.专业技能