Tā dāyìng bāngmáng, jiéguǒ kāitiānchuāng, yī gè rén dōu méi qǐngdào.
He promised to help but ended up leaving it empty-handed — he didn't invite a single person.
Tips
culture
开天窗 (literally 'open a skylight') originates from the press, where a blank white space would be left in place of censored content. The blank looks like a window cut into the page. It can also mean failing to deliver on a promise.
