68. Joining sentences 

• Incorrect: This is my friend, he was at school with me. 

• Correct: This is my friend who was at school with me. 

• Incorrect: This is my house, I live here. 

• Correct: This is my house where I live. 

• Incorrect: This is an interesting story, I am reading it. 

• Correct: This is an interesting story which I am reading. 

Two main clauses which are not separated by a full stop should be linked by a conjunction or a relative pronoun.