Commonly Misused Words

Insure means to establish a contract for insurance of some type.
Ensure means to guarantee.
Assure means to inform with a view to removing doubt

None may be construed as either singular or plural, according to the thought to be conveyed: “no amount” (when the following noun is singular) or “no individuals” (when the following noun is plural).

Right: None of the fruit was eaten.
Right: Not one of the volcanoes in Chile is active.

When the meaning is “not one,” it is better to use not one than none with a singular verb.

Right: Not one of the guests has arrived.

When referring to a quantity, use more than, not over. More than may be used for volumes.

Right: I have more than $5 in my wallet.

While means “at the same time as.” Do not substitute but or and with while.

Wrong: While the council chair was a Democrat that year, the post was held for 20 years thereafter by a Republican.
Right: Although the council chair was a Democrat that year, . . . the post . . .
Right: The council chair that year was a Democrat, but the post was held . . .
Wrong: He is a doctor, while his wife is a dentist.
Right: He is a doctor, and his wife is a dentist.

Who is used for a grammatical subject, where a nominative pronoun such as I or he would be appropriate.

Right: The actor who played Hamlet was there. Who do you think is the best candidate?

Whom is used where an objective (object of) pronoun would be appropriate.

Right: To whom did you give the letter?
Right: The man whom the papers criticized did not show up.

Test by turning the sentence around to say, “The papers criticized the man [him].” Therefore, the objective form (him, whom) is correct in the original sentence.