There are some grammar rules that seem impossible to remember. Should I use lie or lay? Affect or effect? Who or whom?

While words that sound the same but are spelled differently and have different meanings (homophones) are the most commonly confused words (visit Spelling for more information), the following similar word pairs can be equally troublesome [1]–[5].


Word pairs Rules Examples

Use among when the person or thing is part of a group.

Use between when two persons or things are specified.

He is most well known among the five engineers.

He is the most well known between the two engineers.


Use fewer to mean “a smaller number of countable persons or things.”

Use less to mean “a limited number or amount of collective persons or things.”

Rodney has fewer pennies in his pocket than I do.

Lesley has less money in her wallet than she did before lunch.


Use further to mean “to a greater degree or extent,” and as a transition word.

Use farther to mean “at a greater distance.”

We need to research this matter further.

Further, the first widget worked better than the second.

We traveled farther than we expected.


Use infer to mean “to derive a conclusion from facts.”

Use imply to mean “to express indirectly.”

He can infer from the data that the experiment failed.

Her supervisor implied that she may get a raise.


Use lay to mean “to put or place.”

Use lie to mean “to recline.”

Lay the memo on my desk.

I will lie down to rest at the end of the day.


Use past to mean “time period before the present.”

Use passed as the past tense of the verb “pass.”

Projects from the past showed similar outcomes.

He passed the building twice before he finally recognized it.


Use precede to mean “to go before.”

Use proceed to mean “to continue doing something.”

The presentation preceded the discussion on the meeting agenda.

She proceeded with her work after numerous interruptions.


Use who when referring to the subject of a clause (the person or thing performing an action).

Use whom when referring to the object of a clause (the person or thing receiving an action).

She doesn’t know who needs further training.

I don’t care whom you decide to invite.


Use then to express time.

Use than for comparison.

The call is tomorrow. We will talk to her then.

His chair is more comfortable than hers.


[1] R. Rambo. (2012, May 22). Identifying and eliminating common errors in writing. English Composition 1. [Online]. Available:

[2] D.L. Driscoll, K. Stolley, and E. Angeli. (2010, April 17). Commonly confused verbs. Purdue University Online Writing Lab. [Online]. Available:

[3] P. Dahlen. (n.d.). Common mistakes. TransLegal. [Online]. Available

[4] M. Fogarty. (2007, March 9). Who versus whom. Grammar Girl. [Online]. Available:

[5] C. Berry and A. Brizee. (2011, May 9). Using pronouns clearly. Purdue University Online Writing Lab. [Online]. Available: