Get a handle on homonyms, learn what should be capitalized and what shouldn’t, and find out why that extra comma matters so much!
1) apostrophes with possessive nouns
A possessive noun is a person, place, or thing that “owns” or “has” something. Where you place the apostrophe will depend on whether the possessive noun is singular or plural:
The student’s project. (“The student” is a singular noun, so the apostrophe goes before the “s”)
If the noun is plural (meaning, more than one), place the apostrophe after the “s”:
The students’ project. (“The students” is a plural noun, so the apostrophe goes after the “s”)
Do not use an apostrophe for plural nouns that aren’t possessive:
PSU students create the best projects.
2) its and it’s
“It’s” is a contraction of “it is” or “it has.”
“Its” is a possessive pronoun.
It’s (it is) a shame the cat broke its (the cat’s) leg.
3) your and you’re
“You’re” is a contraction of “you are.”
“Your” is a possessive pronoun.
You’re (You are) going to be late for your date.
4) then and than
“Then” refers to time or a sequence of events. “Than” is used when making a comparison.
If you like chocolate more than vanilla, then you will hate my dessert.
5) there, their, and they’re
There is a position, place, or state of being:
Just put that book over there.
There are so many grammar rules!
Their is possessive:
Their office is small.
The students are enjoying their vacation.
They’re is a contraction of they are:
They’re (They are) graduating this spring.
When his parents see his apartment, they’re going to wish they made hotel reservations.
6) lose and loose
“Lose” means unable to find someone or something, or fail to keep or win.
“Loose” means not securely attached, or free from confinement.
You’ll lose the race if your wheels are loose.
7) affect and effect
“Affect” is almost always a verb:
The Internet affects people’s attention spans.
“Effect” is almost always a noun:
The Internet’s effects can also be positive.
- A person’s title only when it comes before his/her name: Professor Jon Smith.
- Specific degree names and course titles: Bachelor of Science in Education; English Composition I.
Do not capitalize when referring to degrees and courses in a general sense:
I’m working on a master’s in history.
Avoid capitalizing words for emphasis: I can’t Believe it! I Won the Lottery!
That “extra” comma people always seem to be arguing about is called an Oxford comma (or serial comma) and it can make all the difference in a sentence:
I would like to thank my parents, Tina Fey and Amy Poehler. (Wow, your parents are Tina and Amy?)
I would like to thank my parents, Tina Fey, and Amy Poehler.
Always use a.m. and p.m. (lowercase, with periods) with a space after the preceding number.
Use single digits for hours without specified minutes: 9 a.m.
But include a colon and numbers for minutes: 9:15 a.m.
Use noon and midnight rather than 12 a.m. or 12 p.m.