Some of the grammar rules you learned in school could be messing up your writing. Flickr / Patrick Gage Kelley Elementary-school students learning how to write simultaneously learn the rules of grammar, and the two approaches can be difficult to balance.

It's why many teachers ingrain in their students a combination of white lies and formal habits that are meant to keep their writing focused but aren't actually based on rules of the English language.

As the students grow into adults, these habits result in plenty of incorrectly worded but well-intentioned sentences.

Harvard cognitive scientist and linguist Steven Pinker explores some of the most common myths and the mistakes they produce in his book "The Sense of Style," which is like a modern version of Strunk and White's classic "The Elements of Style," based on linguistics and updated for the 21st century.

Pinker strips popular grammar guides of the 20th century of their sanctity and instead delves into the evolution of English and how it was constructed and used for centuries to determine what is correct.

Here are some of the grammar myths that may be muddling your writing.

"You can't begin a sentence with a conjunction."

Teachers instruct young students that it is incorrect to begin a sentence with a conjunction (and, because, but, or, so, also) because it helps keep them from writing in fragments, Pinker writes, but it's advice that adults don't need to follow.

Avoid writing an ugly "megasentence" full of connected independent clauses, and feel free to start a sentence with a conjunction.

"All subjects preceding a gerund need to take the possessive form."

H.W. Fowler coined the term "fused participle" in his 1926 book "A Dictionary of Modern English Usage" to denote gerunds with unmarked subjects.

According to Fowler, in She approved of Sheila taking the job, Sheila and taking have become a horrid fused participle, and the only correct form is She approved of Sheila's taking the job.

Pinker argues that the gerunds with unmarked subject format preceded the other form and are grammatically acceptable but not always the best choice in terms of style or clarity.

There are also times when the "rule" results in a poor sentence like I was annoyed by the people behind me in line's being served first and thus should not be seen as restrictive.

Author Steven Pinker, a Harvard professor. Harvard University's Institute of Politics

"Like cannot be followed by a clause or be used to introduce examples."

The word like got a lot of flack from highbrow writers and media folk in 1954 when R.J. Reynolds Tobacco Company premiered the slogan, "Winston tastes good, like a cigarette should." They said that "like" was a preposition, not a conjunction, and could take only a noun phrase object, as in crazy like a fox. The correct form would have taken as, they argued.

Pinker says the morally righteous argument was an incorrect one. Just because like is a preposition doesn't mean it can't take a clausal complement. In fact, that form appears in 600 years of English, including in the works of master writers such as William Shakespeare and Mark Twain. Use like or as freely, Pinker says, and be aware that as is slightly more formal.

Similarly, there's a common "bogus rule" that such as, not like, is the proper way to introduce examples. Both are legitimate. In Many technical terms have become familiar, such as "cloning" and "DNA," the form like "cloning" and "DNA" is also acceptable.

"Possessive antecedents must explicitly precede possessive adjectives."

The following sentence appeared in the verbal section of a 2002 College Board exam, and students were asked to identify an error if there was one: Toni Morrison's genius enables her to create novels that arise from and express the injustices African Americans have endured. The correct response was "no error," but a high-school teacher argued that her was incorrect because it doesn't have a noun to refer back to.

Pinker says that he found this "rule" only in the work of a "usage maven in the 1960s" and that it is simply not based in the construction of English.

The one thing to look out for, he says, is making sure the antecedent is clear. For example, it would be confusing to write Sophie's mother thinks she's fat because it's unclear who she's is referring to.

"You must never use a preposition to end a sentence."

"There is nothing, repeat nothing, wrong with Who are you looking at? or The better to see you with or We are such stuff as dreams are made on or It's you she's thinking of," Pinker writes.

The "pseudo-rule" is entirely based on a 17th-century quibble between the English poet John Dryden and his rival poet Ben Jonson, in which Dryden mistakenly transferred a Latin rule to English. In Latin, Pinker writes, "the equivalent to a preposition is attached to the noun and cannot be separated from it."

Pinker's 2014 book uses extensive research to determine what constitutes good writing. Amazon

"A pronoun serving as the complement of be must be in the nominative case (I, he, she, we, they)."

If the above rule were true, it would be incorrect to say, "Hi, it's me," since it should be, "Hi, it's I." This is another misconception based on equating Latin rules with English rules and declaring formal English as the only acceptable version of the language, Pinker says.

In English, the accusative case (me, him, her, us, them) is the default and "can be used anywhere except in the subject of a tensed verb," Pinker says.

"You must never split an infinitive."

"Most mythical usage rules are merely harmless," Pinker writes, but the "prohibition of split infinitives ... is downright pernicious." According to this pseudo-rule, you can't split the word to from its verb, as in to surrender. Once again, Pinker says, this is based on incorrectly equating Latin with English.

Pinker says following it results in "monstrosities" like Hobbes concluded that the only way out of the mess is for everyone permanently to surrender to an authoritarian ruler.

"Than and as need to precede clauses, not noun phrases."

According to many teaching methods, Rose is smarter than him is the incorrect version of Rose is smarter than he, but Pinker says that both are correct and that the latter is only the formal choice.

"Like the words before and like, which we examined earlier, the words than and as are not conjunctions in the first place but prepositions that take a clause as a complement," he writes. "The only question is whether they may also take a noun phrase as a complement. Several centuries of great writers ... have voted with their pens, and the answer is yes."

"That and which cannot be interchangeably used before clauses."

According to the "rule," nonrestrictive clauses (those set off by commas, dashes, or parentheses) must be introduced by which and restrictive clauses (those that are essential to the sentence) must be introduced by that. Pinker acknowledges that in most situations it sounds better to follow this construction, but rather than being a rule of grammar it is just another invention from H.W. Fowler's "A Dictionary of Modern English Usage."

"New words and usages degrade the language."

Pinker welcomes rather than scoffs at new additions to the dictionary, since languages are living things.

"Neologisms also replenish the lexical richness of a language, compensating for the unavoidable loss of words and erosion of senses," he writes. "Much of the joy of writing comes from shopping from the hundreds of thousands of words that English makes available, and it's good to remember that each of them was a neologism in its day."