Homophones are words that sound alike, but are spelled differently. These words are often used incorrectly in writing. A common misused set of homophones is "to" and "too." The word "to" is a preposition. It refers to direction. "Too" means also or in addition. If you are trying to decide which form of the word you should use, ask yourself if the words "to" or "too" can be replaced with the words "toward" or "also." For instance, you can go to the library. The word "to" in this sentence can be replaced with the word "toward" and the sentence will still make sense. You cannot replace the word "to" with "also" in this sentence. Here is another example: if your friend goes to the library, you can go, too. Can you replace the word "too" with "also?" You sure can. If your friend goes to the library, you can go also. Word replacement is the best way to check your grammar and make sure that you are using homophones correctly.
Another set of easily confused words is "there,"their," and "they're." The word "there" is a pronoun and it refers to a place. You can say, "I want to go there tomorrow." "Their" is a possessive pronoun. This word is used to take the place of two or more people and to shows ownership. For instance, that is their neighborhood. The third word, "they're" is a contraction for "they are." This word is used as a pronoun. If two or more people are watching a movie at the theater, you would say, "they're watching a movie."
When writing or speaking, people often become confused on whether to use "who" or "whom." According to dictionary.com, "who" refers to "what person" and when used correctly, it appears in the subject of the sentence. The subject of a sentence is the noun or pronoun doing the action. The sentence, "Who is going to the library tomorrow?" uses "who" as the subject. The word "whom" is the objective form of "who." This means that the word "whom" receives the action in the sentence. In the sentence, "To whom did the teacher call upon first?" the word "whom" receives the action. Another way to determine correct usage is by replacing "who" with "he" and "whom" with "him." Who (he) is going to the library? I am going to the library with whom? In this last sentence, you can answer the question by saying "I am going to the library with him."