反物质与普通物质相遇时会湮灭并释放巨大能量。

When ___anti-matter comes into contact with normal matter, they annihilate and release tremendous energy.

他的乐观态度与她的消极情绪形成鲜明对比，就像反物质相遇一样。

His optimism was like ___anti-matter to her negativity.