drag on =

(for something unpleasant) To continue for too long
-> His boring speech has been dragging on for one hour.

keep on =

To continue to do something, or to do something repeatedly
-> I never stop studying English. I keep on motivating myself to practice.

go on =

To continue
-> The baseball league goes on until the end of this year.

stay on =

To stay in a place longer than you planned or after other people have left it
-> The class has ended, but I decided to stay on to review the lesson.

= To continue to study at school or university in order to get a higher qualification
-> Those students who prefer staying on have clear vision of their future.

= To continue working in your job
-> I know how hard it is to look for a job, so I am staying on at the company.

Exercises: What is the correct phrasal verb?

1. The president's leadership ___________ for more than 20 years. The country has suffered a lot.
2. You are a good student. Please ___________ until you graduate.
3. ___________ with your practice if you really want to be good at speaking English.
4. The Christmas season in the Philippines ___________ for three months.
5. The music was cut, but he ___________ dancing.

adapted from www.2ndnature-online-eikaiwa.com