Prepositions are small words but they give English speakers big headaches. Some common preposition problems include choosing between different from and different than, or whether to use between or among. You should also pay attention to prepositions because choosing the wrong one may be embarrassing.
Here are a few examples:
Person 1: May I sit next to you?
Person 2: (smiling) Certainly.
Person 1: May I sit under you?
Person 2: (sound of slap) Help! Police!
A few questions in the SAT Writing and the ACT English tests revolve around prepositions. You may encounter a misused preposition (to instead of with, for example) or a situation in which another part of speech grabs a preposition's rightful spot (different than instead of different from, perhaps).
Which is right: Different than or from?
How many times have you heard this sentence?
Prepositions are different than other parts of speech.
You’ve probably heard (and maybe used) the expression different than lots of times. The bad news is different than is never correct. What you want is different from.
You can stop reading right here because now you have all the information you need. If you absolutely have to know why different than is a no-no, continue on. Just be aware that the explanation relies on some technical and therefore annoying grammar points. Here goes: than is not a preposition. It's a conjunction — the part of speech that links two ideas. The catch is that than joins two ideas containing subject-verb combos. (One more grammar term: anything with a subject-verb pair is called a clause.) Here's a sentence in which than is used correctly:
Tracy knows more prepositions than I do.
Did you notice the subject-verb pairs? Tracy knows and I do, one on each side of than, make this sentence correct. Now take a look at the same sentence, which is also correct:
Tracy knows more prepositions than I.
The portion of the sentence following than appears to lack a subject-verb pair. But appearances, as we all know, may be deceiving. In the preceding example sentence, do is understood. Grammatically, both example sentences are exactly the same.
From, on the other hand, is a preposition. It has an object, a noun, or a pronoun. (In rare cases, a clause may be an object of a preposition, but that sort of sentence isn't relevant when you're creating a different from sentence.) Here are a few correct different from sentences, with the object of the preposition italicized:
A preposition is different from other parts of speech.
Lola's new tattoo will be different from her previous fifteen tattoos.
Using between or among in a sentence
Between and among are two tricky prepositions that are often used incorrectly. To choose the appropriate preposition, decide how many people or things you’re talking about. If the answer is two, you want between, as in this sentence:
Lola was completely unable to choose between the biker magazine and Poetry for Weightlifters. (two magazines only)
If you’re talking about more than two, among is the appropriate word:
Lola strolled among the parked motorcycles, reading poetry aloud. (more than two motorcycles)
One exception: Treaties are made between nations, even if more than two countries sign:
The treaty to outlaw bubble gum was negotiated between Libya, the United States, Russia, and Ecuador.
Prepositions at the end of a sentence
Global warming is increasing, the stock market is tanking, and the Yankees’ pitching staff is in deep trouble. In the midst of all these earth-shattering events, some people still walk around worrying about where to put a preposition. Specifically, they worry about whether or not ending a sentence with a preposition is acceptable:
Tell me whom he spoke about.
Tell me about whom he spoke.
Here’s the verdict: Both sentences are correct, at least for most people and even for most grammarians. But, not for all. If you're writing for someone who loves to tsk-tsk about the decline and fall of proper English, avoid placing a preposition at the end of a sentence. Otherwise, put the preposition wherever you like, including at the end of a sentence.