[shí tou]
tone; rock; petr-; petri-; petro-; -lith
lift a stone only to drop it onto one's own feet
搬起石头砸自己的脚
a heap of stones
一堆石头
cut a stone
凿石头
stumble over a stone
被石头绊了一跤
rive a stone
劈开一块石头
Stones whet a sword, difficulties strengthen willpower.
石头是刀的朋友， 障碍是意志的朋友。