這就怪了.
我還去查了一下, 我沒有看到 injection 有 "充血" 的意思.
醫學上, injection 絕大部份是指 "注射".
這是 google 上寫的:
What is throat infection?
A throat infection, sometimes called pharyngitis, can be either a bacterial or a viral infection leading to inflammation of the tissues of the throat that causes redness, pain and swelling of the walls or structures of the throat.
所以喉嚨發炎英文可以寫成 throat infection. 當然, 最常用的說法是 sore throat 或是throat inflammation.
如果你去 google 查一下, throat injection 出現最多的是 "深喉口暴"
