[shí tou]
tone; rock; petr-; petri-; petro-; -lith
lift a stone only to drop it onto one's own feet
搬起石頭砸自己的腳
a heap of stones
一堆石頭
cut a stone
鑿石頭
stumble over a stone
被石頭絆了一跤
rive a stone
劈開一塊石頭
Stones whet a sword, difficulties strengthen willpower.
石頭是刀的朋友， 障礙是意志的朋友。