Grammatically Correct: The writer's essential guide to punctuation ...

Ellipsis ( ... )
The ellipsis (from the Greek "to leave out" or "fall short") has three
distinct functions:
• Indicating omissions in quoted material
• Indicating hesitation or trailing off in spoken words
• Imparting extra significance to a sentence
INDICATING O:MISSIONS
You may abridge a quotation, but you must not pass off your abridged
version as the original. If you take anything out, you must put an
ellipsis in its place to let the reader know that something is missing.
Ellipses are needed only when you drop something from within
a quoted passage, or if you need to clarify that a quotation is beginning
or ending in midsentence. Do not use them if you are presenting
selected excerpts or obvious sentence fragments.
There is no limit to how many words you may take out of a
quotation, but be sure that the fragments you leave hold together
grammatically. More importantly, be certain that you are not distorting
or misrepresenting the meaning of the original. It is fine to drop
words that are irrelevant for your purposes, but the message and
the spirit of the source must be retained.
If you are altering or adding any text to a quotation, use brackets
instead (see page 166).
The following shows how an original passage may be abbreviated
using ellipses.
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