Common English Mistakes by Graduate Students
This was originally prepared by Robert
M. Keller, with additional contributions by Gary Lindstrom.
A few more have been added since then.
Below is a list of English grammatical errors commonly committed by PhD students.
Please try to understand these items, and check your paper for all of these
errors before submitting it.
In addition, do not submit a draft of anything unless it has been
[Caution: I have committed in several places below one sin of fighting
convention, namely to put closing quotation marks where they logically
belong, rather than according to typographer's convention. Thus, if a
quoted phrase lies within, but at the end of, a sentence, I would put the
closing quote before the period. I believe this is done correctly
in England. -- RMK]
- Number agreement between subject and verb: In English, nouns
and verbs have number (i.e. singular: one, and plural: more
than one). Quite often, but not always, the plural of a noun is
formed by adding "s" or some variant, as in "computer" --> "computers",
"matrix" --> "matrices", etc. The opposite is true for verbs:
a plural verb will often have no "s", but the singular version is
obtained by adding "s": "computes" (singular) --> "compute (plural).
Thus, "computers compute using electronics", but "this computer
computes using electronics". We say "the scheme utilizes . . ." but
"the schemes utilize . . .". (One might formulate this as the
"conservation of s" law.) Not all verbs follow the "s" pattern;
for example "are" is the plural form of "is", "had" is both singular
and plural, "criteria" is the plural of "criterion", "data" is the
plural of "datum", "media" is the plural of "medium", etc. Check
a dictionary if in doubt.
- Number in possessive pronouns: "their" refers to
several possessors, while "its", "his", and "her" refers to a single
one. ("John and Mary use their personal computer to . . .",
"The computer gets its power from . . .")
- Its: "its" is a possessive pronoun. "it's" is a contraction
of "it is". The two are not interchangeable.
- Dangling prepositions: Phrases should not be ended with prepositions
(e.g. "to", "with"). For example, instead of "the output port the memory
is connected to" use "the output port to which the memory is
connected". A good way of remembering this is to recall the
tongue-in-cheek rule: "A preposition is something you should never end
a sentence with".
- Generic versus specific: Different constructions are used for
generic and specific statements. We say "computers compute" when we are
talking about computers in general, but "the computer computes" when we
are talking about a specific computer (mentioned earlier usually).
The word "the" is called the "definite article", because it refers to
a specific thing or set of things ("article" is the term used for words
"the", "a", "an"). The article "the" is used for both ("the computers
in MEB"). The plural generic uses no article ("computers compute using
electronics"). The singular generic used "a", as in "a computer computes
- "a" vs. "an": The article "an" is used before words which begin
with a vowel sound, whereas "a" is used before words which begin
with a consonant sound.
- "good" vs. "well": There are two kinds of modifiers:
adjectives, which modify nouns, and adverbs, which modify
verbs or adjectives. "good" is an adjective ("It is a good scheme".)
while "well" is an adverb ("The scheme works well".).
- Discrete vs. continuous (or countable vs. uncountable): The
words "many", "few", and "several" refer to discrete objects ("There
are few computers which . . .", "Several algorithms exist for . . .").
The words "much" and "little" refer to uncountable commodities ("I
have little patience . . .", "There is much to be learned . . .", but
"There are many things to be learned . . ."). Similarly, "less" is
continuous, while "fewer" is discrete: "Give me less soup and fewer
beans"; "more" is used for both: "Give me more bananas and more
water". (But some things with a discrete character are discussed as
if they were continuous: "My program uses less memory", but "My data
require fewer bits".)
- Commas should be used where you would normally pause if you
were reading the sentence aloud. However, they should be used
only where there is possible ambiguity in parsing the
sentence without them.
- "like" vs. "as": "like" is used to compare two similar things
or concepts: "A circulating memory is like a shift register". "as" is
used to conjoin phrases: "A circulating memory behaves the same as
a shift register".
- Inappropriateness of verb to subject, e.g. "Computers as
inanimate machines argue for intelligence in their use" ("Computers"
do not "argue", etc.). Examine each sentence to locate the subject
and verb, and be sure they make sense as isolated pairs.
- If you have trouble expressing a complex sentence, it most
surely should be broken into two or more new sentences.
Edward P. J. Corbett, The little English handbook, 3rd edition, Wiley (1980)
(softbound, about $6.95). Highly recommended, but may be a bit technical for
foreigners. Includes proofreaders marks, various forms.
Wm. Strunk, Jr. and E. B. White, The elements of style, Macmillan (1959).
A standard reference on style and usage.
G. A. Barnes, Communication skills for the foreign-born professional,
ISI Press, Philadelphia (1982). Includes useful information on written and
other forms of communication. Recommended for natives as well.
Provided by Art Lee without permission from the original authors. Last modified on March 20, 2000.