问题
选择题
Nature reserves are very important for preserving many animals and plants, which would _______ run the risk of becoming extinct.
A．otherwise
B．therefore
C．though
D．instead
答案
答案：A
题目分析：A否则，要不然；B因此；C然而；D代替，而不是；句意：对于保护很多野生动植物来说自然保护很重要，要不是这些动植物会有灭绝的危险。根据句意说明A项符合上下文。