A cavity in a solid的用法和样例：
- A cavity in a solid.
- A solid filling, as of gold or porcelain, fitted to a cavity in a tooth and cemented into place.
- I have a cavity in a tooth and it's very painful.
- That is actually a cavity in the earth.
- (dentistry) a solid substance (as gold or porcelain) fitted to a cavity in a tooth and cemented into place.