a lump of clay的用法和样例：
- I worked up a lump of clay into a bust.
- Fashion a lump of clay into a bowl.
- She has worked up a lump of clay into a bust.
- The artist started with a big lump of clay.
- Ward Cunningham : I like the notion of working the program, like an artist works a lump of clay.
- He showed Huck the fragment of candle-wick perched on a lump of clay against the wall, and described how he and Becky had watched the flame struggle and expire.