After losing seven of the last eight Democratic presidential contests, Hillary Clinton spent Wednesday hammering rival Bernie Sanders in anticipation of New York’s make-or-break primary.

In separate campaign stops and interviews, Clinton questioned Sanders’ competence, credentials and commitment to gun control.

“He hasn’t done his homework” on reining in Wall Street or curbing gun violence, Clinton said on MSNBC.

Hours later, she bashed the Vermont socialist for promoting economic plans that “just won’t work because the numbers don’t add up.”

“In a number of important areas, he doesn’t have a plan at all,” Clinton told AFL-CIO union members at a rally in Philadelphia. “You got to know what you want and you got to have a plan for getting it or people aren’t going to get the help that they need.”

Caught on a hot mike talking to a supporter after the speech, Clinton revealed concern that her campaign isn’t catching fire. “We’ve got to get the energy going,” she was overheard saying.

The Clinton campaign on Wednesday put forward supporters to denounce Sanders’ opposition to efforts by families of Sandy Hook shooting victims to sue gun manufacturers.

Jillian Soto, who lost her sister in the massacre, called Sanders’ position “not only offensive” but “insensitive and disrespectful to the families involved.”

The Vermont senator responded angrily.

“What happened in Sandy Hook is a tragedy beyond comprehension, but maybe Secretary Clinton might want to apologize to the families who lost their loved ones in Iraq,” he told CBS, alluding to her Senate vote to authorize the 2003 invasion.

And Sanders’ campaign manager warned Clinton to tone down her attacks.

“Don’t destroy the Democratic Party to satisfy the secretary’s ambitions to become president of the United States,” Jeff Weaver warned on CNN.

Clinton responded: “It’s just ludicrous on the face of it. You know, I have been campaigning for Democrats, fundraising for Democrats, recruiting Democrats to run and win for a really long time . . . Senator Sanders, by his own admission, has never even been a Democrat.”