Советы иностранцам, изучающим английский

100's/hundreds

It looks cheesy to spell "hundreds" as "100's"; and it isn't really
logical because "100" doesn't mean "hundred" — it means specifically "one
hundred."

360 DEGREES/180 DEGREES

When you turn 360 degrees you've completed a circle and are back where
you started. So if you want to describe a position that's diametrically
opposed to another, the expression you want is not "360 degrees away"
but "180 degrees away."

A/AN

If the word following begins with a vowel sound, the word you want is
"an": "Have an apple, Adam." If the word following begins with a
consonant, but begins with a vowel sound, you still need "an": "An X-ray
will show whether there's a worm in it." It is nonstandard and often
considered sloppy speech to utter an "uh" sound in such cases.

The same rule applies to initialisms like "NGO" (for "non-governmental
organization"). Because the letter N is pronounced "en," it's "an NGO"
but when the phrase is spoken instead of the abbreviation, it's "a
non-governmental organization."

When the following word definitely begins with a consonant sound, you
need "a": "A snake told me apples enhance mental abilities."

Note that the letter Y can be either a vowel or a consonant. Although it
is sounded as a vowel in words like "pretty," at the beginning of words
it is usually sounded as a consonant, as in "a yolk."

Words beginning with the letter U which start with a Y consonant sound
like "university" and "utensil" also take an "a": "a university" and "a
utensil." But when an initial U has a vowel sound, the word is preceded
by "an": it's "an umpire," "an umbrella," and "an understanding."

See also "an historic."

A.D.

"A.D." does not mean "after death," as many people suppose. "B.C."
stands for the English phrase "before Christ," but "A.D." stands
confusingly for a Latin phrase: anno domini ("in the year of the
Lord" — the year Jesus was born). If the calendar actually changed with
Jesus' death, then what would we do with the years during which he
lived? Since Jesus was probably actually born around 6 B.C. or so, the
connection of the calendar with him can be misleading.

Many Biblical scholars, historians, and archeologists prefer the less
sectarian designations "before the Common Era" (B.C.E.) and "the Common
Era" (C.E.).

Traditionally "A.D." was placed before the year number and "B.C." after,
but many people now prefer to put both abbreviations after the numbers.

All of these abbreviations can also be spelled without their periods.

ALA / A LA

If you offer pie a la mode on your menu, be careful not to spell it "ala
mode" or — worse — "alamode." The accent over the first "a" is optional in
English, although this is an adaptation of the French phrase a la mode
de meaning "in the manner of." The one-word spelling used to be common;
but as people became more sensitive to preserving the spelling of
originally French phrases, it fell out of favor. In whose manner is it
to plop ice cream on your pie? Nobody really knows, but it's yummy.
Stick with the two-word spelling in all other uses of the phrase "a la"
as well.

AM/PM

"AM" stands for the Latin phrase Ante Meridiem — which means "before
noon" — and "PM" stands for Post Meridiem : "after noon." Although digital
clocks routinely label noon "12:00 PM" you should avoid this expression
not only because it is incorrect, but because many people will imagine
you are talking about midnight instead. The same goes for "12:00 AM."