Apostrophes show omitted letters or figures, show possession, and separate confusing combinations of letters.
Use apostrophes to create contractions. (The formal they are becomes the casual they're.)
Mind your p's and q's when using apostrophes.
Use apostrophes to show possession, before the s for singular and after for plural.
Example:
The boy's balloon. (One boy with one balloon.)
The boys' balloons. (More than one boy with more than one balloon.)
To learn more, see:
Quotation marks indicate direct use of someone else's words and titles of short works.
They indicate someone's exact words, either quoted from speech or from another source.
They are not used for emphasis.
They can occasionally be used for sarcasm (then they are called scare quotes).
Double quotation marks are almost always the correct choice. Single quotation marks are used for quotes inside quotes and in newspaper style.
To learn more, see: