For many of us, the proper use of that and which causes confusion, but the grammar rules for determining when to use that or which are simple.
Use that to introduce restrictive clauses. A restrictive clause is a clause that cannot be removed without changing the meaning of the sentence.
- Writing that is filled with grammatical errors makes the writer appear less knowledgeable.
- Writing that has not been checked for spelling and grammatical errors is not ready for publication.
- Articles that have not been proofread should not be submitted.
Removing the restrictive clause in these sentences changes the meaning of the entire sentence.
Use which before a nonrestrictive clause. Nonrestrictive clauses add additional information, but do not alter meaning. Nonrestrictive clauses are often enclosed in parenthesis, and can be removed completely without changing the meaning of the sentence.
- Free grammar and spelling checkers, which can be found on the Internet, help writers polish their work.
- Confusion over word choice, which is very common, causes careless errors.
Removing a nonrestrictive clause does not change the meaning of the sentence.
Use who to introduce any clause when the subject is a person.
- Writers who follow grammar rules produce clean copy. (restrictive clause)
- Online writers who ignore the importance of keywords and SEO often get frustrated when their writing fails to draw in readers. (restrictive clause)
- Successful online writers, who take their work seriously, know the importance of good grammar and SEO techniques. (nonrestrictive clause)
Most word processing programs contain a grammar and spelling checker, but if yours does not, you can use free grammar and spelling checkers online to double-check your work. Spelling and grammar checking software is also available for sale, if you prefer to use a program from your computer.