抛砖pāo zhuān
(1) 抛出【好查hao86.com】砖去，引回玉来。比喻自谦以粗浅的见解引出别人的高见
例
方才婢子费了唇舌，说了许多书名，原是抛砖，以为借此长长见识。——清·李汝珍《镜花缘》
英
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
