Student or Learner
1. The students who are laborious are successful.
2. The students, who are laborious, are successful.
I suppose there's some difference in meaning between these two, but I can't figure out this difference.
NOT A TEACHER
(1) My sister who is a physician is very kind. (But my sister who is a journalist is a
very rude -- and unpopular -- person.)
(2) My sister, who is a physician, is the nicest person that you would ever want to
know. (I probably have only one sister.)
My wife, who is an English grammar expert, is very patient with people who do
not know grammar as well as she. (I have only one wife. That's the law in my country.)
My wife who is an English grammar expert is very patient with people who do not
know grammar as well as she. But my wife who is a journalist is quite rude to people.
And my wife who is a pilot is neither kind nor rude. She's just so so. (I have
three wives. The law in my country permits it.)