Bring out the difference in meaning between the following pair of sentences.
A 1) My sister,who is a doctor, has gone to England.
2) My sister who is a doctor has gone to England.
B 1) He must work hard to do well in the exams.
2) He must work hard and do well in the exams.
A 1) My sister, who is a doctor, has gone to England.
In this sentence, the dependent clause 'who is a doctor' has been emphasised.
2) My sister who is a doctor has gone to England.
In this sentence, 'my sister' is the subject on which emphasis is laid upon.
B.1) He must work hard to do well in the exams.
In this sentence, cause and effect relationship is there. 'He must work hard so that he can do well in the exams.
2) He must work hard and do well in the exams.
In this sentence, two independent clauses are joined by a conjunction. Both may or may not be linked with each other.