I thought I was running out of pet peeves after the first or second of these grammar-oriented e-letters, or maybe it was the third. But I’m not, and apparently neither are my readers.

1. Like or as?

If you have to ask, it’s probably as. When we make comparisons, like is for nouns and as is for phrases that include verbs:

YES  Winston tastes good as a cigarette should.
YES I feel like a cat on a hot tin roof.

Mind you, like and as both have all sorts of other uses. This one rule doesn’t encompass the entire universe of the use of either like or as. It only helps you determine which one to use when making an explicit comparison.

How to get it right

Use like  if and only if you can substitute similar to. Otherwise, use as.

? Winston tastes good similar to a cigarette should.

That doesn’t work! Use as.

? I feel similar to a cat on a hot tin roof.

In this case, like is correct.

P.S. It should be “I’ve got the moves like Jagger‘s.” (Terrible song, pretty good video.) Then I’m comparing my moves with Jagger’s moves. Otherwise, I’m comparing my moves with Mick himself, which would be even dumber than comparing myself with Mick.

2. Insure, ensure, or assure?

These three similar words have quite different meanings. Insure and ensure in particular are often confused, but distinguishing them could not be easier.

Insure: guarantee against loss
Ensure: secure, make sure or certain
Assure: state with confidence, promise or pledge

YES We assure you that we have done everything to ensure the success of this circus, including insuring the big top for $4 million.

How to get it right
To assure involves communicating with someone else. To insure involves taking out an insurance policy. Most other cases take ensure, which is less concrete or easily defined than the other two.

3. Honing pigeon

A simple error we hear all the time in speech has now crept into writing.

NO We wanted to hone in on the reasons the big top fell. NO NO NONO!

Hone means sharpen.

YES We honed our analytic skills by looking into the reasons the big top fell.

When you are zeroing in on something, getting closer to the target—whether literally or figuratively—you want home in on.

YES We homed in on the reasons the big top fell.

How to get it right
Think “homing pigeon.”

4. The reason why is because

Newscasters are notorious for this one, but it’s also creeping into writing.

NO  The reason the big top fell is because the center pole buckled.

Or, worse yet:

NO The reason why the big top fell is because the center pole buckled.

Talk about redundant! Reason, why, and because all mean essentially the same thing.

YES The reason the big top fell is that the center pole buckled.

How to get it right
It’s “the reason… is that….” Period. Don’t put reason together with either why or because.

5. Who or whom?

I really thought I had already covered this one, but several of readers asked. Here’s the skinny:

  • Who is, grammatically, a subject. Use it when you can substitute he or they.
  • Whom is an object. Use it when you can substitute him or them.

(Yes, she and her also work, but the m in him or them helps you remember the m in whom.)

? Who/m brought the big top down?

This one is easy. You can substitute he or they, so the correct interrogative pronoun is who.

YES Who brought the big top down?

Sometimes, however, you have to unwind a sentence.

? The detective interviewed every roustabout who/m had worked on the big top.
? Who/m did the detective interview?

In the first sentence, who is the subject of the clause that follows. You would write “They had worked on the big top.” So the correct pronoun is who.

YES The detective interviewed every roustabout who had worked on the big top.

In the second example, you may have to change the word order of the sentence from its current interrogative form to the declarative form—from a question to a statement. Who is doing the interviewing here? The detective is. That makes  detective the subject of the sentence: “The detective did interview them.” So the question goes:

YES Whom did the detective interview?

How to get it right
Try substituting he for who and him for whom. If you are a native speaker of English, your ear will tell you which is right.

Another way to get it right
Hire someone who knows.