“I knew a man with a wooden leg named Smith.”

“What was the name of his other leg?”

When I first saw “Mary Poppins” as a 9-year-old, those two lines struck me as nothing more than a silly joke, though they do turn out to be a plot point. When I saw it again in October at the breathtaking United Palace Theater in Washington Heights, I of course recognized the first line as a dangler — a misplaced modifier. Since named Smith is supposed to modify man rather than leg, the sentence should read I knew a man named Smith with a wooden leg. But that wouldn’t make 9-year-olds (or editors) laugh.

Danglers can cost writing one of its most prized attributes: clarity. But they’re only one of many kinds of mistakes that do.

Like many students (and professional reporters long out of school), a 2015 J-school graduate from India was not 100 percent crystal-clear when she wrote:

The L train stops, and a young student dressed in black oversized vintage sweater and jeans and black boots gets down.

“Were the jeans black?”  I asked. Readers might assume so, but you don’t want them to assume, any more than they want you to assume they know what you mean. Here’s one way to clarify:

The L train stops, and a young student dressed all in black — oversized vintage sweater, jeans and boots — gets down.

If the jeans weren’t black, I’d say oversized black vintage sweater, jeans and black boots. When multiple adjectives precede a noun, the rule is that the most important goes closest to the noun, the next most important before that, etc. Which is which is a matter for the writer  — or editor — to decide.

One of my favorite recent examples came in a July New Yorker article about political conventions. The Harvard history professor Jill Lepore wrote:

“Interviewing a candidate is about as intimate as catching him on television,” Norman Mailer wrote from the Republican Convention in Miami in 1968, to which some G.O.P. genius had flown in a pachyderm. “Therefore the reporter went to cover the elephant.”

Reading this passage on the subway, I did a double take (“a rapid or surprised second look, either literal or figurative, at a person or situation whose significance had not been completely grasped at first,” according to dictionary.com). Someone had flown to the convention in a pachyderm (an elegant variation on elephant)? Suddenly I had a vision of another Disney movie: “Dumbo.” Then I looked again and laughed. Lepore, an exemplary writer, was using flown in as a phrasal verb, an idiomatic combination of verb + adverb with a special meaning. She meant the elephant had been flown in to the convention — brought to Miami by plane — but I had read the sentence literally. That possibility apparently didn’t occur to The New Yorker’s legendary copy editors. It should have.

Phrasals can be especially confusing in headlines, which are either upstyle (all important words are uppercase) or downstyle (only proper nouns are).  In upstyle heds, adverbs are capped, while prepositions of fewer than four letters generally are not. I hoped for the best when I saw this in The New York Times, whose news sections are upstyle:

Head off Trump in the Midwest