抛砖引玉（抛磚引玉|抛甎引玉）　

◎ 抛砖引玉 pāozhuān-yǐnyù

[throw out a brick to attract a jade;(fig) offer a few commonplace remarks by way of introduction so that others may come up with valuable opinions] 抛出砖去,引回玉来。比喻自谦以粗浅的见解引出别人的高见

方才婢子费了唇舌,说了许多书名,原是抛砖引玉,以为借此长长见识。——清· 李汝珍《镜花缘》