doctor said that the patient would die ____ he was sent to hospital immediately

问题描述:

doctor said that the patient would die ____ he was sent to hospital immediately
A. then B. but C.except D.unless 希望能详细的解释下 . 为什么 .

D除非 医生说那个病人会死,除非他被及时送往医院 A然后 B但是 C除了