will not withhold one's advice or suggestion ? 望各位參觀者～，以便我們改進。I hope that the visitors will not withhold their suggestions so that improvements will be made.
不吝金玉bù lìn jīn yù
金玉：指寶貴的意見。不吝惜寶貴的意見。not niggardly with gold and gem, not withhold one’s advice or suggestion