All successful movements have a moment when they gather momentum. The great push for civil rights acquired its force thanks to Rosa Parks and the buses of Montgomery. The Free Speech Movement helped create the climate for mass opposition to the Vietnam War.

It’s possible that the attack in Parkland, Fla., will be that defining moment for the movement against rampant gun violence in the United States.

The courageous students of Marjory Stoneman Douglas High School, who lost 17 of their classmates and school staffers allegedly to a 19-year-old with an assault rifle, have set in motion a reaction that goes beyond politics.

Their voices have shamed a host of corporations — airlines, car rental outfits, moving companies, a bank — into cutting ties with the National Rifle Association. Major retailers, including Walmart and Dick’s Sporting Goods, have tightened gun-sale policies.

Most people think the NRA is a citizen group intent on protecting the constitutional right to bear arms.

It’s not. It’s the political arm of a gun manufacturing industry intent on increasing sales. And as long as politicians were doing the talking, the NRA’s money and ability to organize a committed voter base held the upper hand.

But now we have a new voice. High school students from all over the country will be heading to Washington on March 24 for a demonstration demanding tighter controls on guns. Those who can’t make it to the capital will be marching in 50 other cities.

It took nearly a decade between Montgomery and the passage of landmark civil rights legislation. America was mired in Vietnam until the early 1970s. Movements take time to accomplish their goals — we won’t have meaningful gun control next week.

The good news is, the generation that is driving this movement will only be gathering strength and power in the years to come.

China soul: How do you make a Black History Month event succeed at a Chinatown senior center? Just ask Malcolm Yeung with the Chinatown Community Development Center.

Yeung called me up and said, “Mayor Brown, we want to have a cooking class on Southern food as part of the program. Can you recommend anyone?”

“Malcolm, those seniors don’t speak English,” I said. “Isn’t that going to be a problem?”

“Don’t worry, we’ll make it work.”

The next thing I knew, I was sitting in the back of the center’s social room, listening to my friend Bryant Terry give a lecture on how to prepare greens and sweet potato pie — all of it being translated into Cantonese.

It must have been a hit, because now the seniors are asking Chinese bakeries for sweet potato pie by its English name, and chef Terry tells me that a number have signed up for a post-graduate cooking lecture at the Museum of the African Diaspora.

Speechless: I had the unenviable task of taking over for the late Rose Pak at the finish line of the Chinese New Year Parade. Pak used to crack wise over the microphone as the politicians rolled by, and I’m afraid I was no match.

Pak, the longtime political powerhouse, dubbed the diminutive Supervisor Aaron Peskin “the Napoleon of North Beach” at one parade.

I thought I was ready with one for Peskin as the caravan of classic cars carrying local officials approached the reviewing stand. “Here he is, fresh from the backroom deal that made Mark Farrell mayor,” seemed appropriate.

Suddenly there’s a rhythmic “Boom! Boom! Boom!” thumping. I look up, and here comes this cherried-out pneumatic lowrider right out of the Mission, with Peskin bouncing up and down atop the back seat.

They say one picture is worth a thousand words. In this case, the picture left me speechless.

The envelope, please: The Academy Awards are Sunday night, so it’s time for me to go out on my usual limb:

•Best actress: Frances McDormand for “Three Billboards Outside Ebbing, Missouri”

•Best actor: Gary Oldman for “Darkest Hour”

•Best supporting actor: Sam Rockwell for “Three Billboards”

•Best supporting actress: Allison Janney for “I, Tonya”

•Best director: Guillermo del Toro for “The Shape of Water”

•Best picture: It should be “Three Billboards,” but it will be “The Shape of Water”

More movie time: “The 15:17 to Paris.” My friend Clint Eastwood, who has won two Oscars as a director, didn’t pick the best material or cast for this one.

I thought it would disappear in a week. Wrong again.

Civic-minded: Former Mayor Art Agnos was spotted picking up litter on the street in his Potrero Hill neighborhood.

“Mr. Mayor, what are you doing?” asked a passerby.

“I’m helping pay for my retirement,” Art replied.

An honest politician to the end.