I know it's optional, but is it necessary?

外籍病人，詢問醫生。

Doctor: "The vaccine is recommended by government, but it is optional."
Patient: "I know it's optional, but is it necessary?"

這就像問「我知阿媽係女人，但佢係咪男人呢？」

隨意選擇和必需，是明顯對立的詞語。

他大概不是在使用矛盾修飾吧。

病人可能在想，自己應否接種此疫苗。考慮因素，包括價錢、副作用和風險等。

Amendment: "I know it's optional, but shall I receive the vaccination?"