We proofread hundreds of documents every week, so you would expect that we'd come to know the most common mistakes made in English business writing.
One of them has to do with a particular form of "is." Yes, it seems the most common mistake in writing today is the false contraction "it's." For example, "The throng made it's way to the center of the field."
Think this mistake is beneath you? Think again! A surprising number of well-educated people make this mistake in writing. Perhaps they're just writing too quickly. Or perhaps they're among those who may have just slept through fifth-grade English or eleventh-grade composition.
The word "it" is a pronoun. The word means "that one" and is either a subject or an object in a sentence. But here's something interesting: did you know that "its" is not a pronoun, but an adjective? Yes, "its" is an adjective describing the noun that follows. Make sure you never confuse the adjective "its" with the pronoun-verb construct "it's."
Variations on this mistake surround the use of "is." The contractions "that's," "what's," and "it's" -- plus the contractions formed with a noun and "is" (e.g., "Gracie's here today" and "The coop's not quite finished yet") -- are often avoided in formal writing.