If you let the boy go without punishment , he will use it as a（ ）for doing wrong again.
A、president
B、precedent
C、supposition
D、identification
【正确答案】：B
【题目解析】：本题考查词义辨析。president：总统，国家主席；precedent：先例，传统，常例，常规；supposition：推测，推断；identification：鉴定，辨认，确认。句意：如果你不惩罚他就放他走，他会把这当作再次犯错误的先例。故B选项符合题意。
