The most common uses of these two words are illustrated in this sentence:
You affect [verb meaning change] people when you have an
effect [noun meaning impact] upon them.
Rarely, affect can be used as a noun to describe the mannerism or behavior pattern of a person. (As a noun, it's pronounced with emphasis on the first syllable.) This noun version of
affect is used most often by psychiatrists to describe the
mannerisms of their patients or subjects. However, others might legitimately use the noun version of
affect as well:
The exotic dancer had a pronounced affect [mannerism] to her walk as she left the room.
Sometimes effect is used as a verb meaning bring about. (As a verb, the first syllable is pronounced by most people as a long "e" rather than an "uh" sound, but emphasis is still on the second syllable.) Here is an example of this usage:
We knew that if we all worked together, we could effect [bring
about] a change in our system of government.
The only possible meaning of it's is the contraction for it
is. If that's not the meaning you intend, use its (a possessive pronoun) instead. (Pronouns
never use apostrophes to show possession.)
When referring to humans, use who or whom in such contexts as these:
Mary was the person who crossed the street just now.
For whom does the bell toll?
When referring to animals or inanimate objects, use that:
The gazelle was the animal that narrowly escaped the lion.
The dog that left a present in your front yard is my pet.
The Melville classic was the book that caused such a sensation.
Trying to decide which of these words to use in a sentence can be a real challenge, but here's a helpful tip to determine which is correct: Substitute
he or him or else they or them for the word in question. If the word that sounds more natural in the sentence contains an
m (i.e., him or them), use whom or whomever. If the word that sounds more natural does
not contain an m (i.e., he or they), use who or
whoever. You'll be right every time and be a big hit at parties! (Okay,
okay, just kidding about the parties.)
