这把单发手枪需要每次射击后重新装弹。

This ___single-shot pistol needs to be reloaded after each firing.

这种疫苗只需单次注射就能提供长期保护。

This vaccine offers long-term protection with just a ___single-shot injection.

这次考试是一次性的机会，所以你必须全力以赴。

This exam is a ___single-shot opportunity, so you must give it your all.