Learning English can, at times, be a daunting task. Of all the languages in the world, English is not always the most straightforward, and for newcomers not having any immersion in the language, it can be that much more difficult.
In this post, I want to highlight five of the most common English mistakes I see in people’s writing and how students and teachers alike can avoid them.

Affect vs. Effect

I get more questions about these two words than any other words I know. Many students will actually go out of their way to avoid using these words, but once you get the hang of them, they aren’t scary at all.
The best way to explain these words to students is to remind them that affect is almost always used as a verb, and effect is usually used as a noun. If you can get your students to remember this simple trick, they will avoid 95 percent of potential misuses with these words.

Who vs. Whom

Who and whom are probably the words I get asked about second most. These two words can be tough to keep track of; plus, they are a little more difficult to remove from your sentences than affect and effect.
The important part to remember about these two words is how they function within your sentences. Who is used as a subject, and whom is used as an object. A good mnemonic to teach students is to substitute the word in question with he/him. If he makes sense in the sentence, use who. If him makes sense, use whom.

• You gave your shoes to whom? (him)
• Who (he) is that man?

I versus Me

A lot of writers think it’s more formal to use I instead of me.

• After the movie, John took Suzy and I for a boat ride.

Not only is this not “formal,” but it’s also incorrect. Just like who/whom, I and me both have specific functions in a sentence. I functions as a subject while me functions as an object.
So when you are the subject of the sentence, use I.

• Suzy and I went for a boat ride after the movie.

But when you are the object, you must use me.

• After the movie, John took Suzy and me for a boat ride.

Using Like as a Conjunction

Like can be many things in a sentence, but, in formal writing, it cannot be a conjunction. Like functions primarily as a preposition, so it therefore takes objects, but you shouldn’t be seeing any verbs following it.

• These tourists act like they’ve never seen snow before today. (Wrong)
• These people act as if they’ve never seen snow before today. (Correct)
• I play the piano just like you. (Correct)
• I play the piano just like you do. (Wrong)

Run-on Sentences

Run-on sentences are surprisingly common in student writing, yet it’s easy to avoid if students carefully read their sentences.
A run-on sentence is nothing more than two independent clauses that are placed together without a joining word or any punctuation.

• We need to leave soon the movie is about to start.

This is a run-on sentence, but we can easily fix it by adding a period, semicolon, or a conjunction.

• We need to leave soon. The movie is about to start.
• We need to leave soon; the movie is about to start.
• We need to leave soon because the movie is about to start.

Once your students master these five common mistakes, they will be well ahead of even most native English speakers and writers.
To see a more complete list of common writing mistakes, please check out my e-book 35 Mistakes to Avoid in Your Writing or visit the Confusing Words section of WritingExplained.org.