【题目】---Are you for the idea?
--- (正相反), I'm against it.

【答案】On the contrary
【解析】On the contrary 考查介词短语。短语on the contrary恰恰相反，该短语表示上下文的转折关系。句意：—你支持这个观点吗？—恰恰相反，我反对它。