语法与词汇 26.Since the adoption of these techniques there has not been a single case of______of HIV or hepatitis via plasma products. Doctors agree that plasma products from paid donors are just as safe as those from unpaid ones.
【正确答案】 C
【答案解析】这两句话的意思是：自从采用这些技术以来，没有出现一例通过血浆产品传播艾滋病毒或肝炎的案例；医生们一致认为，来自有偿捐赠者的血浆产品和来自无偿捐赠者的血浆产品一样安全。transmission意为“传播、广播”；transaction意为“交易、处理”；transition意为“过渡、更替”；transformation意为“改变、转变”。因此正确答案为C。