Free The Blue Book of Grammar and Punctuation by Jane Straus, Lester Kaufman, Tom Stern Page A

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During the '80's and '90's, the U.S. economy grew .
    Rule 12 . You may also express decades in complete numerals. Again, it is cleaner to avoid an apostrophe between the year and the s .
Example :
During the 1980s and 1990s, the U.S. economy grew .

Chapter 5
Confusing Words and Homonyms
    Many words in English sound or look alike, causing confusion and not a few headaches. This chapter lists some of these words, and other troublemakers.
A
    A, AN
    Use a when the first letter of the word following has the sound of a consonant. Keep in mind that some vowels can sound like consonants, such as when they're sounded out as individual letters. Also, some letters, notably h and u , sometimes act as consonants ( home, usual ), other times as vowels ( honest, unusual ).
Examples :
a yearning
a hotel
a U-turn (pronounced “yoo”)
a NASA study
    Use an when the first letter of the word following has the sound of a vowel.
Examples :
an unfair charge
an honor (the h is silent)
an HMO plan ( H is pronounced “aitch”)
an NAACP convention (the N is pronounced “en”)
    ABBREVIATION, ACRONYM
    This is a fine distinction that some consider nitpicking. Terms such as FBI, HMO , and NAACP , although widely called acronyms, are actually abbreviations. The difference is in how they are spoken. An abbreviation , also called an initialism , is pronounced letter by letter. An acronym is pronounced as if it were a word. The abbreviation FBI is pronounced “eff-bee-eye.” The acronym NASA is pronounced “nassa.”
    ACCEPT, EXCEPT
    Accept means “to acknowledge” or “to agree to.”
    Except is usually a preposition used to specify what isn't included: I like all fruits except apples .
    ACRONYM
    See abbreviation, acronym .
    AD, ADD
    Ad : short for “advertisement.”
    Add : to include; to perform addition.
    ADAPT, ADOPT
    To adapt is to take something and change it for a special purpose. A screenwriter adapts a book to make it work as a movie. An organism adapts (itself) to a new environment.
    To adopt is to take something and use it or make it your own. A government adopts a different policy. A family adopts an orphan.
    ADVERSE, AVERSE
    Adverse : unfavorable: an adverse reaction to the medication .
    Averse : not fond of; seeking to avoid: averse to risk .
    ADVICE, ADVISE
    Advice : guidance.
    Advise : to suggest; to recommend.
    AFFECT, EFFECT
    Affect as a verb means “to influence”: It affected me strangely . As a noun, it is a technical term used in psychology to describe someone's emotional state.
    Effect as a noun means “result”: It had a strange effect on me . As a verb, it means “to bring about” or “to cause”: He's trying to effect change in government .
    AGGRAVATE
    This word is not a synonym for annoy or irritate . To aggravate is to make something worse: He started running too soon and aggravated his sprained ankle .
    AHOLD
    You can get hold of something, and you can get a hold of it. But in formal writing, “ahold” is not a real word.
    AID, AIDE
    An aid is a thing that helps.
    An aide is a living helper or assistant: His aide brought first aid .
    AIL, ALE
    Ail : to be ill.
    Ale : an alcoholic beverage.
    AISLE, ISLE
    Aisle : a corridor.
    Isle : an island.
    ALL READY, ALREADY
    All ready means that everything or everyone is now ready.
    Already refers to something accomplished earlier: We already ate .
    ALL RIGHT
    Two words. Someday, alright may finally prevail, but it hasn't yet.
    ALL-TIME RECORD
    The team set an all-time record for consecutive games won . Delete all-time . All records are “all-time” records.
    Similarly, avoid “new record.” The team set a record, not a new record.
    ALL TOGETHER, ALTOGETHER
    All together : in a group: We're all together in this .
    Altogether : entirely: It is not altogether his fault .
    ALLUDE, ELUDE, REFER
    Allude means “to mention indirectly.” Do not confuse allude with refer . If