Two rules that many people learned at school are less strict than they seem: do not use like where as fits, and never end a sentence with a preposition. In formal writing it can still pay to follow them, but in most texts a sentence that sounds natural matters more than either rule.
To write well in English, you need many things: correct spelling and punctuation, good ideas, and the ability to put those ideas down on paper. You also have to follow the standard rules of grammar. It may surprise you, though, that two things long considered common grammar errors might not be errors at all:
- using like instead of as
- ending a sentence with a preposition
Like vs. as
Generally speaking, these are the rules to follow when you decide between like and as.
Before a noun or a pronoun on its own, like is the usual choice, because here it works as a preposition: She sings like a bird. As also appears before a noun, in fixed comparisons such as (as) blind as a bat, and when it means "in the role of": She works as a teacher.
Before a clause, a subject with its verb, traditional grammar says that you must use as, because as is a conjunction and like is not. This is the tricky one, because following the rule can make a sentence sound odd. Here is the same sentence with each word. By the traditional rule, one of them is correct and the other one is wrong. Can you tell which is which?
- No one cooks pasta like my grandmother does.
- No one cooks pasta as my grandmother does.
The traditional rule calls the first sentence incorrect and the second one correct. Yet the second one sounds stiff, and most people would say the first. Many dictionaries now accept like as a conjunction in everyday English, but careful formal writing still avoids it.
Use common sense here. Follow the rule when the sentence still sounds right. When it does not, rephrase: No one cooks pasta the way my grandmother does is correct by any rule and sounds natural. In casual writing, a sentence that flows well matters more than the strict rule. Like vs. as explains the difference in more detail.
Ending a sentence with a preposition
If you have done any writing at all, you have probably heard that you should not end a sentence with a preposition. You have probably also noticed that this is sometimes very hard to avoid. Some people put a preposition at the end of a sentence at the top of their list of common grammar errors, but it does not belong there.
The rule goes back to grammarians who modelled English on Latin, where a preposition cannot end a sentence. Some old-school teachers still treat it as one of the big rules of writing. In real-world English, however, the rule is much more relaxed. In most cases, it matters far more that a sentence makes sense and reads naturally than that it follows this outdated rule. Compare:
- Who are you talking to?
- To whom are you talking?
Both are correct, but the second one sounds formal, almost old-fashioned. In the same way, This is the house I grew up in is perfectly good English, and This is the house in which I grew up is correct too, only heavier. Rules like this one change over time: who decides what is right or wrong in English grammar? explains how.
Of course, if your teacher is one of the old-school teachers who still enforce this rule, follow it in their class.
Why spelling still matters
Now you know the real rules behind two items that some people consider grammar errors, even though they are not always errors. That is not all you need, though. Even if you choose the right words and express your thoughts well, misspellings can cost you your readers and your credibility. Before you send your work out into the world, check it with the Spell Checker, which marks spelling, grammar, and punctuation mistakes.